US20040243018A1 - Apparatus and method for determining adequacy of electrode-to-skin contact and electrode quality for bioelectrical measurements - Google Patents
Apparatus and method for determining adequacy of electrode-to-skin contact and electrode quality for bioelectrical measurements Download PDFInfo
- Publication number
- US20040243018A1 US20040243018A1 US10/724,458 US72445803A US2004243018A1 US 20040243018 A1 US20040243018 A1 US 20040243018A1 US 72445803 A US72445803 A US 72445803A US 2004243018 A1 US2004243018 A1 US 2004243018A1
- Authority
- US
- United States
- Prior art keywords
- electrode
- measurement
- body part
- voltage
- electrodes
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Images
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/43—Detecting, measuring or recording for evaluating the reproductive systems
- A61B5/4306—Detecting, measuring or recording for evaluating the reproductive systems for evaluating the female reproductive systems, e.g. gynaecological evaluations
- A61B5/4312—Breast evaluation or disorder diagnosis
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B10/00—Other methods or instruments for diagnosis, e.g. instruments for taking a cell sample, for biopsy, for vaccination diagnosis; Sex determination; Ovulation-period determination; Throat striking implements
- A61B10/0041—Detection of breast cancer
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/05—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves
- A61B5/053—Measuring electrical impedance or conductance of a portion of the body
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/05—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves
- A61B5/053—Measuring electrical impedance or conductance of a portion of the body
- A61B5/0531—Measuring skin impedance
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/68—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient
- A61B5/6801—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be attached to or worn on the body surface
- A61B5/6843—Monitoring or controlling sensor contact pressure
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
- A61B2017/00017—Electrical control of surgical instruments
- A61B2017/00022—Sensing or detecting at the treatment site
- A61B2017/00026—Conductivity or impedance, e.g. of tissue
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
- A61B2018/00053—Mechanical features of the instrument of device
- A61B2018/0016—Energy applicators arranged in a two- or three dimensional array
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B90/00—Instruments, implements or accessories specially adapted for surgery or diagnosis and not covered by any of the groups A61B1/00 - A61B50/00, e.g. for luxation treatment or for protecting wound edges
- A61B90/06—Measuring instruments not otherwise provided for
- A61B2090/064—Measuring instruments not otherwise provided for for measuring force, pressure or mechanical tension
- A61B2090/065—Measuring instruments not otherwise provided for for measuring force, pressure or mechanical tension for measuring contact or contact pressure
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B2562/00—Details of sensors; Constructional details of sensor housings or probes; Accessories for sensors
- A61B2562/02—Details of sensors specially adapted for in-vivo measurements
- A61B2562/0219—Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/24—Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
- A61B5/25—Bioelectric electrodes therefor
- A61B5/276—Protection against electrode failure
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/24—Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
- A61B5/25—Bioelectric electrodes therefor
- A61B5/279—Bioelectric electrodes therefor specially adapted for particular uses
- A61B5/28—Bioelectric electrodes therefor specially adapted for particular uses for electrocardiography [ECG]
- A61B5/282—Holders for multiple electrodes
Definitions
- This invention relates to medical diagnosis of disease and specifically relates to diagnosis of disease using electrical impedances of body parts.
- the onset of disease is often accompanied by physical changes in a body part. Some physical changes, while not discernible by a patient, can be detected with appropriate diagnostic equipment, often at a relatively early stage of the disease. For example, the electrical impedance of a human breast can have diagnostic value.
- Tetrapolar impedance measurements are associated with injecting current between so called current injection electrodes and measuring a voltage drop between associated electrodes.
- the differences between corresponding homologous impedance measurements in the two body parts are compared in a variety of ways that allows the calculation of metrics that can serve either as an indicator of the presence of disease or to localize the disease to a specific breast quadrant or sector.
- Electrodes array having a plurality of electrodes in contact with the skin covering the underlying breast tissue. If one or more electrodes have lost contact with the skin, or if the contact with the skin is poor, errors can arise in the electrical measurements that then yield erroneous impedances.
- the present invention provides a method to determine both if there is electrode contact with the skin, and, if there is such contact, what the quality of that contact is.
- the method involves making bipolar measurements of the impedance.
- ⁇ is the frequency at which the voltage (and current) oscillates
- C is the capacitance of the circuit.
- phase associated with a body part of a patient at a particular frequency can be found by making bipolar measurements. By comparing the phase, at one or several frequencies, to expected values, a decision can be made as to whether the electrode is in suitable contact with the skin on the body part.
- bipolar measurement is better for determining adequacy of electrode-to-skin contact (herein referred to as either “contact” or “electrode contact”) because a poor contact result can be isolated to one or both electrodes.
- phase instead of the magnitude is advantageous because a) impedance magnitude varies greatly from person to person, b) stray capacitance in the system can cause a smaller observed impedance value than would be expected from the high open-circuit value associated with a disconnected electrode, and c) sweat or some other substance could allow a low impedance to be registered even though the current traversing the skin is reduced because of poor electrode contact.
- Measuring the phase at different frequencies allows this measure to be even more precise because it can identify if excessive oil or other materials obstruct the skin-electrode interface.
- the expected value for human skin at each of these frequencies is considered. With multiple frequencies, the measured ratio between measured impedance values at different frequencies can be compared to the expected values oh human skin.
- the system includes an electrode array containing a plurality of electrodes capable of being electrically coupled to the body part, and a first measurement unit for making an electrode assessment measurement for the electrode array.
- the system also includes an electrode assessment module for determining whether the plurality of electrodes are suitably coupled to the body part based on the electrode assessment measurement.
- the system further includes a second measurement unit for making a diagnosis measurement with the electrode array, and an electrical property module for obtaining an electrical property, such as electrical impedance, of the body part based on the diagnosis measurement.
- a diagnosis module utilizes the electrical property to diagnose the possibility of disease.
- the plurality of electrodes includes a current injection electrode pair and an associated voltage measurement electrode pair that are applied to the body part.
- One current injection electrode of the current injection electrode pair and one proximal voltage measurement electrode of the voltage measurement electrode pair are used by the first measurement unit to make a bipolar measurement.
- the electrode assessment module can include a phase module for obtaining a phase, ⁇ , from the bipolar measurement, whose absolute value is given by
- the electrode assessment module may further include a contact module for determining that at least one of the current injection electrode and the voltage measurement electrode is not in electrical contact with the body part if the phase is outside a threshold range.
- I is the current and V is a resultant voltage measured during the bipolar measurement
- a quality module for determining quality of electrical contact of the current injection electrode and the voltage measurement electrode with the body part based on the magnitude.
- the electrode assessment module may include a) a phase module for obtaining a phase that is a function of a capacitive reactance, at a particular frequency, and a resistance, associated with the body part, and for obtaining other phases at other frequencies, and b) a contact module for determining that at least one of the current injection electrode and the voltage measurement electrode is not in electrical contact with the body part based on the phase at the particular frequency and the other phases at the other frequencies.
- the plurality of electrodes mentioned above can include n CI current injection electrode pairs and n CI associated voltage measurement electrode pairs that are applied to the body part.
- the second measurement unit injects a first current between a first pair of the n CI current injection electrode pairs, measures the resultant voltage difference V 1 M between the voltage measurement electrode pair associated with the first current injection electrode pair, and repeats the preceding two steps of current injection and voltage difference measurement with the other electrode pairs until all n CI voltage differences, ⁇ V 1 M , V 2 M , . . . , V n CI M ⁇ are obtained.
- the electrical property module is an impedance module that uses the n CI voltage differences to obtain associated measured impedances, ⁇ Z 1 M , Z 2 M , . . . , Z n CI M ⁇ , where Z j M is the measured impedance between the voltage electrodes associated with the jth current injection electrode pair.
- the system can then further include a diagnosis module for utilizing the measured impedances, ⁇ Z 1 M , Z 2 M , . . . , Z n CI M ⁇ to diagnose the possibility of disease.
- the system may also include a graphical user interface to indicate a status of the coupling between the plurality of electrodes and the body part.
- the present invention describes a system and/or method for measuring an electrical property, such as impedance, in a living tissue that includes an electrode array, first and second measurement units, an electrode assessment module, and an electrical property module, which are described in more detail below.
- FIG. 1 shows a block diagram of the system for diagnosing the possibility of disease, according to the teachings of the present invention
- FIG. 2A shows the electrode array of FIG. 1.
- FIG. 2B shows a side view of a schematic of a particular current injection electrode pair and an associated voltage measurement electrode pair on the electrode array of FIG. 1.
- FIG. 3 shows the electrode assessment module of FIG. 1.
- FIG. 4 shows a graphical user interface (GUI) that illustrates the status of the skin-electrode contact, according to the teachings of the present invention.
- GUI graphical user interface
- FIG. 5 shows a block diagram of a system for measuring a voltage in a body part, according to the teachings of the present invention.
- FIGS. 6 A-D shows modes of the controller switching unit of FIG. 5.
- FIG. 7 shows a hybrid mode of the controller switching unit of FIG. 5.
- FIG. 8 shows electrical connections in a particular tetrapolar impedance measurement that employs the system of FIG. 5.
- FIGS. 9A and 9B show the multiplexer of FIG. 5.
- FIG. 10 shows a diagnostic system that includes an internal load in addition to the components of FIG. 5.
- FIG. 11 shows one embodiment of the controller switching unit, according to the principles of the present invention.
- FIG. 1 shows a system 100 for diagnosing the possibility of disease in a body part.
- the system 100 includes an electrode array 102 containing a plurality of electrodes 104 capable of being electrically coupled to the body part.
- the system 100 also includes a first measurement unit 106 , an electrode assessment module 108 , a second measurement unit 110 , an electrical property module 112 and a diagnosis module 114 .
- the plurality of electrodes 104 are applied to the body part to obtain an electrical property of the body part, such as impedance, to diagnose disease.
- the plurality of electrodes 104 have to be electrically connected to the body part.
- adhesive means (not shown) can be used to connect the electrodes 104 to the skin on the body part of a subject.
- the electrode conductive material generally a hydrogel, can also have adhesive properties.
- the combined adhesive means can fail, resulting in an electrode that is not in proper electrical contact with the body part.
- the first measurement unit 106 utilizes the electrode array 102 to make an electrode assessment measurement.
- the electrode assessment module 108 determines whether the plurality of electrodes 104 are adequately coupled to the body part based on the electrode assessment measurement, as described in more detail below.
- the second measurement unit 110 can then utilize the electrode array 102 to make a diagnosis measurement.
- the electrical property module 112 obtains an electrical property of the body part, such as an impedance of the body part, based on the diagnosis measurement.
- the diagnosis module 114 diagnoses the possibility of disease based on the electrical property. For example, cancer may change the impedance of the body part, a fact that can be exploited by the diagnosis module 114 to diagnose the possible presence of cancer.
- FIG. 2A shows the electrode array 102 of FIG. 1.
- the electrode array 102 includes the plurality of electrodes 104 that are applied to the body part.
- the plurality of electrodes 104 include current injection electrodes 120 and voltage measurement electrodes 122 (two of these electrodes are labeled for simplicity).
- the electrode array 102 contains several arms 123 (one arm is labeled for simplicity). Each arm includes a current injection electrode and a voltage measurement electrode.
- the arm 125 includes a particular current injection electrode 124 and voltage measurement electrode 126 .
- current injection and “voltage measurement” refer to their use during tetrapolar measurement, as used in this invention for the diagnosis stage.
- an inner pair of electrodes is provided on some of the array arms 123 .
- One particular inner set of electrodes 128 i and 130 i is located on arm 127 . By positioning the inner set of electrodes partway on the array arms, these electrodes are placed closer to the nipple area of the breast, thus allowing better detection of cancers in the periareolar area of the breast.
- FIG. 2B shows a side view of the particular current injection electrode 124 and the voltage measurement electrode 126 on the arm 125 . Also shown in FIG. 2B is another arm 127 of the electrode array 102 having another current injection electrode 128 and voltage measurement electrode 130 .
- a single electrode is used for both current injection and voltage measurement.
- current is injected between electrodes 124 and 126 , and voltage is measured between electrodes 124 and 126 . More specifically, current is injected through electrode 124 into the body part, then is received from the body part through electrode 126 . The resultant voltage difference between electrodes 124 and 126 is measured by a voltmeter 131 .
- the first measurement unit 106 is used to make the bipolar impedance measurement between electrodes 124 and 126 , yielding a reactance X C and a resistance R
- the result of this bipolar measurement is used to assess whether the electrodes on the arm 125 are suitably coupled to the body part before a tetrapolar measurement is performed to diagnose disease.
- adjacent electrodes 124 and 126 are used to perform the bipolar measurements. This choice is dictated by the fact that a measurement is more likely to yield predominantly electrode-to-skin contact impedance if the distance between the two electrodes used is very small.
- FIG. 3 shows the electrode assessment module 108 of FIG. 1.
- the electrode assessment module 108 includes a phase module 132 , a magnitude module 134 , a contact module 136 and a quality module 138 .
- the phase module 132 obtains a phase ⁇ from the bipolar measurement according to
- the contact module 136 uses the phase calculated by the phase module 132 to determine whether at least one of the electrodes 124 and 126 does not make adequate electrical contact with the body part. In particular, if the phase lies outside a threshold range, then the electrodes 124 and/or 126 fails to make adequate electrical contact with the skin.
- a useful index for this determination is the ratio X C /R, with X C /R ⁇ 0.80 at 50 kHz indicating failed contact.
- the relationship between the phases at each frequency is used to make the contact determination. Particularly, as frequency increases, the phase of the impedance reduces. If the measured phase at one frequency is larger than a measured phase at a lower frequency, something other than skin is making contact.
- the magnitude module 134 obtains an impedance magnitude
- the quality module 138 uses the magnitude
- the first measurement unit 106 makes bipolar measurements that allow the electrode assessment module 108 to determine a) whether the electrodes 124 and 126 are in adequate contact with the skin, as ascertained from the phase information and b) whether the conductive quality of the hydrogel component of electrodes 124 and 126 has been maintained or has deteriorated, as ascertained from the impedance magnitude. It should be understood that the electrode-to-skin contact of other electrodes can also be assessed. For this purpose, another bipolar measurement can be performed using another two electrodes on another arm of the electrode array to provide information about the suitability of the contact, and so on.
- FIG. 4 shows a graphical user interface (GUI) that illustrates the status of the electrode-to-skin contact.
- GUI graphical user interface
- a display 150 shows two representations 152 and 154 of electrode arrays 102 , the representation 152 of the right breast array and the representation 154 of the left breast array.
- Each electrode array representation has twelve arms 156 .
- each electrode array representation has sixteen arms.
- the colour of the circles 158 indicates which electrodes have been ascertained to be in contact with the skin.
- a red circle indicates an inadequate contact
- a blue circle indicates an adequate one.
- Other indicators are possible, such as flashing circles representing inadequate contacts.
- white circles represent electrodes making adequate contact
- black circles represent those that are not. This determination is made by the contact module 136 .
- the quality module 138 furnishes its information at the bottom of the display.
- a bar 160 is shown with various levels of electrode quality with, in this example, three usable level—excellent, Good, and Pass—and one unacceptable level—Replace. If the quality is excellent, for example, then the word “Excellent” is highlighted on the bar 160 .
- Both electrode contact and quality information are made available to the user administering the diagnostic examination in real time.
- the user can take immediate steps to rectify a poor electrode-to-skin contact, or replace a deteriorated electrode, before proceeding with the diagnostic testing.
- the ability to display real time information is a direct result of using bipolar measurements for making the status determination.
- bipolar measurements one measurement relates to one electrode pair, and only the number of measurements as there air pairs is required to refresh the display. If tetrapolar measurements were used to make the contact determination, each measurement would include four electrodes and many sets of measurements per pair would be required to make the contact determination. Performing all of these measurements would take much longer.
- the display 150 shown can be a computer or television monitor. In other embodiments, LED lights can signal electrode status.
- the system 100 can proceed to the diagnosis stage.
- the second measurement unit 110 injects a first current between a first pair of the n CI current injection electrode pairs, and then measures the resultant voltage difference V 1 M between a voltage measurement electrode pair.
- current travels from a current injection electrode of a first arm to a current injection electrode of a second arm, then the voltage difference is measured between the voltage measurement electrodes of the same two arms.
- current can flow between electrodes 124 and 128 .
- the associated resultant voltage is measured between electrodes 126 and 130 .
- n CI current injections are possible with an equal number of associated voltage measurements.
- n CI current injections are possible with an equal number of associated voltage measurements.
- the impedance module 112 uses the n CI voltage differences to obtain associated measured impedances, ⁇ Z 1 M , Z 2 M , . . . , Z n C IM ⁇ where Z j M is the measured impedance between the voltage electrodes associated with the jth current injection electrode pair.
- the diagnosis module 114 utilizes the measured impedances, ⁇ Z 1 M , Z 2 M , . . . , Z n CI M ⁇ to diagnose the possibility of disease.
- U.S. Pat. No. 6,122,544 describes a method that compares impedances between homologous body parts. In this method, the impedance of a body part of a patient is compared to the impedance of the homologous body part of the same patient. A difference between these two impedances could signal disease.
- the system 100 employs both tetrapolar and bipolar measurements to assess the quality of electrode contact.
- a diagnostic system 1000 capable of both these types of measurements will now be described.
- FIG. 5 shows a system 1000 for measuring a voltage in a body part 110 , such as a human breast.
- the system 1000 includes N body leads 120 .
- the N body leads 120 are ordered from 1 to N for reference.
- the system 1000 also includes a multiplexing unit 140 having a multiplexer 160 , a first MX lead 180 , a second MX lead 200 , a third MX lead 220 and a fourth MX lead 240 .
- the system 1000 further includes a controller switching unit 260 having a first switch 280 connected to the multiplexer 160 by the first MX lead 180 and the second MX lead 200 , a second switch 300 connected to the multiplexer 160 by the third MX lead 220 and the fourth MX lead 240 , a current input lead 320 connected to the first switch 280 , a current output lead 340 connected to the second switch 300 , a first voltage lead 360 connected to the first switch 280 , and a second voltage lead 380 connected to the second switch 300 .
- the controller switching unit 260 also includes a controller 390 .
- the system 1000 further includes an impedance module 400 and a diagnosis module 420 .
- FIG. 5 Also shown in FIG. 5 is an optional second set of leads 440 that can be used when making measurements on a second homologous body part 460 .
- the description below is directed mainly to an impedance measurement on the one body part 110 with the set of N leads 120 , but it should be understood that the discussion could be analogously expanded to include an impedance measurement on the second homologous body part 460 with the second set of leads 440 .
- the principles of the present invention can be applied to diagnosis of disease by making electrical measurements on a single body part, or by making measurements on a homologous pair of body parts. When making measurements on only a single body part, the results can be compared to standard results obtained from population studies, for example, to diagnose disease. When using a homologous pair of body parts, the results of one body part can be compared to the results of the homologous body part of the same patient, as described in U.S. Pat. No. 6,122,544.
- the N body leads 120 electrically connect the multiplexing unit 140 to the body part 110 .
- Each of the N body leads 120 includes a wire capable of carrying a current and an electrode to attach to the body part 110 .
- a current conducting gel can act as an interface between the electrode and the skin covering the body part 110 .
- the multiplexing unit 140 and the controller switching unit 260 allow a current to flow through the body part 110 between any two body leads, n 1 and n 2 , of the N body leads 120 , and a resultant voltage to be measured between any two body leads, n 3 and n 4 of the N body leads 120 , where n 1 ⁇ n 2 and n 3 ⁇ n 4 , but where n 1 , n 2 , n 3 and n 4 need not otherwise be distinct.
- the impedance module 400 generates current that is injected into the current input lead 320 and then delivered to the body part.
- the current output lead 340 receives the current from the body part.
- the first voltage lead 360 and the second voltage lead 380 are used to measure the resultant voltage between these leads 360 and 380 .
- the impedance module 400 uses this voltage, together with the known current injected into the current input lead 320 , to calculate a corresponding impedance, which may then be used by the diagnosis module 420 to diagnose disease.
- N is even and the multiplexer 160 can electrically connect the first MX lead 180 and the fourth MX lead 240 to a first set of N/2 of the N leads, and the second MX lead 200 and the third MX lead 220 to a second set of the other N/2 leads.
- the first set of N/2 leads are exclusively used to inject current into and receive current from the body part.
- the second set of N/2 leads are then exclusively used to measure resultant voltages in tetrapolar measurements. This configuration limits the number of impedances that can be measured.
- the second set of N/2 leads can also be used to inject and receive current, and the first set can be used to measure resultant voltages.
- the system 1000 can furnish a greater number of impedances.
- the system can make both tetrapolar and bipolar measurements.
- the added benefits arise from the functionality of the controller switching unit 260 .
- the system 1000 can force current to flow through the body part 110 between any two body leads, n 1 and n 2 , of the N body leads 120 , and a resultant voltage to be measured between any two body leads, n 3 and n 4 of the N body leads 120 , where n 1 ⁇ n 2 and n 3 ⁇ n 4 .
- FIGS. 6 A-D show several states of the switches 280 and 300 resulting in different modes of the controller switching unit 260 of the system of FIG. 5. These states of the switches 280 and 300 are controlled by the controller 390 .
- current is injected into the first MX lead 180 and received by the fourth MX lead 240 . While this current travels through the body part 110 , a resultant voltage is measured between the second MX lead 200 and the third MX lead 220 . This measurement is tetrapolar because current is forced to flow between two leads and the resultant voltage is measured between two other leads.
- FIGS. 6A and 6B the first switch 280 and the second switch 300 are both in tetrapolar states since, for each of the switches 280 and 300 , two distinct MX leads are involved in the impedance measurement.
- the controller switching unit 260 is said to be in a tetrapolar mode.
- FIGS. 6A and 6B correspond to tetrapolar modes.
- the current input lead 320 is electrically connected to exactly one of the first MX lead 180 and the second MX lead 200 and the first voltage lead 360 is electrically connected to the other one of the first MX lead 180 and the second MX lead 200 ; likewise, the current output lead 340 is electrically connected to exactly one of the third MX lead 220 and the fourth MX lead 240 and the second voltage lead 380 is connected to the other one of the third MX lead 220 and the fourth MX lead 240 .
- the two tetrapolar modes shown in FIGS. 6A and 6B do not exhaust all the tetrapolar modes.
- the controller switching unit 260 is also in a tetrapolar mode.
- the controller switching unit 260 is in a tetrapolar mode when n 1 , n 2 , n 3 and n 4 are distinct, where n 1 and n 2 are leads from among the N leads 120 used to inject current into and receive current from the body part 110 , and n 3 and n 4 are leads used to measure the resultant voltage.
- FIG. 6C current is injected into the first MX lead 180 and received by the fourth MX lead 240 . While this current travels through the body part 110 , a resultant voltage is measured between the first MX lead 180 and the fourth MX lead 240 .
- the second and third MX leads 200 and 220 are electrically unconnected to any of the N body leads 120 during this measurement. This measurement is bipolar because the pair of electrodes used for measuring a voltage is also used for current flow.
- FIG. 6D current is injected into the second MX lead 200 and received by the third MX lead 220 .
- the resultant voltage is measured between the same two leads 200 and 220 .
- the first and fourth MX leads 180 and 240 are electrically unconnected during this measurement. This measurement is also bipolar.
- FIGS. 6C and 6D the first switch 280 and the second switch 300 are both in bipolar states since, for each of the switches 280 and 300 , only one MX lead is involved in the impedance measurement.
- the controller switching unit 260 is said to be in a bipolar mode.
- FIGS. 6C and 6D correspond to bipolar modes.
- the current input lead 320 and the first voltage lead 360 are electrically connected to each other and to exactly one of the first MX lead 180 and the second MX lead 200
- the current output lead 340 and the second voltage lead 380 are electrically connected to each other and to exactly one of the third MX lead 220 and the fourth MX lead 240 .
- the two modes shown in FIGS. 6C and 6D do not exhaust all bipolar modes.
- FIG. 7 shows a hybrid mode of the controller switching unit 260 of FIG. 5.
- the first switch 280 is in a tetrapolar state and the second switch 300 is in a bipolar state.
- n 1 ⁇ n 3 and n 2 n 4
- the lead n is electrically connected to the first MX lead 180 or to the fourth MX lead 240 via the multiplexer 160 .
- the lead n 2 is connected to whichever of first MX lead 180 and the fourth MX lead 240 is not connected to the lead n 1 .
- the lead n 3 is connected to the second MX lead 200 or the fourth MX lead 240 , and the lead n 4 is connected to whichever of the second MX lead 200 and the fourth MX lead 240 is not connected to the n 3 lead.
- the third MX lead 220 is electrically unconnected during this hybrid measurement.
- FIG. 8 shows electrical connections in a particular tetrapolar impedance measurement that employs the system 1000 of FIG. 5.
- N 32.
- the second set of leads 440 is also not shown in the FIG. 8 .
- All the electrodes 1-5 of the first set can be electrically connected to the first and fourth MX leads 180 and 240 , and all the electrodes 6-10 of the second set can be connected to the second and third MX leads 200 and 220 via the multiplexer 160 .
- the electrodes 2 and 5 are used to measure the resultant voltage.
- current is generated by the impedance module 400 and sent to the current input lead 320 . From there, the current travels to the first MX lead 180 via the first switch 280 and from there to the electrode 6 via the multiplexer 160 . The current next travels through the body part 110 to the electrode 9 and then through the multiplexer 160 to the fourth MX lead 240 . The current then flows to the current output lead 340 via the second switch 300 and then back to the impedance module 400 . The resultant voltage is measured between the first and second voltage leads 360 and 380 , which corresponds to the voltage between the electrodes 2 and 5.
- the first voltage lead 360 is connected to the electrode 2 via the first switch 280 and the multiplexer 160
- the second voltage lead 380 is electrically connected to the electrode 5 via the second switch 300 and the multiplexer 160 .
- the controller 390 controls the states of the switches 280 and 300 and the multiplexing states in the multiplexer 160 that determine through which leads current flows and which leads are used to measure voltage.
- FIG. 9A shows the multiplexer 160 of FIG. 5 in an embodiment in which a body part is being compared to a homologous body part.
- the multiplexer 160 includes a first body part multiplexer 520 that includes a first body part A multiplexer unit 540 and a first body part B multiplexer unit 560 .
- the multiplexer 160 also includes a second body part multiplexer 580 that includes a second body part A multiplexer unit 600 and a second body part B multiplexer unit 620 .
- the first body part A multiplexer unit 540 is connected to the first MX lead 180 and the fourth MX lead 240 .
- the first body part B multiplexer unit 560 is connected to the second MX lead 200 and the third MX lead 220 .
- the second body part A multiplexer unit 600 is also connected to the first MX lead 180 and the fourth MX lead 240
- the second body part B multiplexer unit 620 is also connected to the second MX lead 200 and the third MX lead 220 .
- the first body part multiplexer 520 is used for multiplexing electrical signals to the first body part of the homologous pair.
- the first body part A multiplexer unit 540 and B multiplexer unit 560 are both capable of multiplexing current and voltage signals to and from the N leads 120 .
- the second body part multiplexer 580 is used for multiplexing electrical signals to the homologous body part.
- the second body part A multiplexer unit 600 and B multiplexer unit 620 are both capable of multiplexing current and voltage signals to and from the N leads 120 , as described below.
- FIG. 9B shows the first body part A multiplexer unit 540 of FIG. 9A.
- the multiplexer unit 540 includes four one-to-N/4 multiplexers 640 , 660 , 680 and 700 . These, for example, can be model number MAX4051ACPE manufactured by MAXIMTM.
- the N/4 multiplexer current leads 720 connect the multiplexer 640 to the multiplexer 680
- N/4 multiplexer current leads 740 connect the multiplexers 660 and 700 .
- the leads 720 and 740 are connected to the first N/2 of the N leads 120 .
- the multiplexers 640 , 660 , 680 and 700 each have a configurable one bit “inhibit state” and log 2 (N/4) bit “control state.”
- the inhibit state can be either off (0) or on (1) and determines whether current can flow through the respective multiplexer 640 , 660 , 680 or 700 .
- the inhibit state of the multiplexer 640 is 1 (on) and the state of the multiplexer 660 is (0,0,0,1), where the first bit is for the inhibit state, and the last three bits identify which lead of multiplexer 660 is being activated, then current destined for the breast is directed to the tenth lead, provided the states of the switches 280 and 300 connect the current input lead 320 to the first MX lead 180 , as previously described.
- this lead 180 when the multiplexer 660 is in the state (0,0,0,1), measures the resultant voltage with the tenth lead.
- a similar binary code for the multiplexers 680 and 700 dictates through which one of the first 16 electrodes of the 32 leads 120 current is received from the breast, provided the states of the switches 280 and 300 connect the current output lead 340 to the fourth MX lead 240 . If the fourth MX lead 240 is not connected to the current output lead 340 , but is connected to the second voltage lead 220 , then the fourth MX lead 240 is used for measuring the resultant voltage, provided the inhibit state of the multiplexer 680 or the multiplexer 700 is off.
- the B multiplexer unit 560 is similar to the A multiplexer unit 540 in that it has four one-to-N/4 multiplexers analogous to 640 , 660 , 680 and 700 .
- the one-to-N/4 multiplexers are capable of connecting with the second and third MX leads 200 and 220 , instead of the first and fourth MX leads 180 and 240 .
- the inhibit and control states determine which electrode from among the other N/2 electrodes is used to deliver current or measure voltage.
- the inhibit and control states are set by the controller 390 with a shift-register and/or a computer.
- a direct digital stream can be sent to the shift register for this purpose.
- the function of the second body part multiplexer 580 is analogous to that of the first body part multiplexer 520 and therefore need not be described further.
- FIG. 10 shows a diagnostic system 820 that includes an internal load 840 in addition to the components described above in relation to FIG. 5.
- the internal load 840 is electrically connected to the first MX lead 180 , the second MX lead 200 , the third MX lead 220 and the fourth MX lead 240 .
- the internal load 840 is used for at least one of internal testing of the system 820 and varying the measurement range of the system 820 .
- the internal load 840 can be connected to the impedance module 400 in a tetrapolar mode or in a bipolar mode.
- the internal load 840 has a known impedance and therefore can be used to test the diagnostic system 820 .
- the internal load 840 can be used to change the measurement range of the system 820 .
- the system 820 is capable of measuring larger impedances than would otherwise be possible. If the resistance of the internal load 840 is R int and is in parallel, the measured resistance R is given by
- R load is the resistance of the load. Consequently, the measured resistance is reduced from the value without the internal load, thereby increasing the measurement range of the system 840 .
- the switches 280 and 300 allow current to flow between various pairs of electrodes on a body part, and resultant voltage to be measured between various pairs of electrodes, as described above with reference to FIGS. 5-10.
- FIG. 11 another embodiment of the controller switching unit is shown that can be used to achieve the states of FIGS. 6 A-D using a different electrical circuit topology.
- the controller switching unit 900 of FIG. 11 includes a first switch 920 and a second switch 940 .
- the current input lead 320 , the current output lead 340 , the first voltage lead 360 and the second voltage lead 380 split to connect to both the first and second switches 920 and 940 .
- the switches 920 and 940 can be turned on or off and can be used to make tetrapolar and bipolar measurements. With only one of the switches 920 and 940 on, a tetrapolar measurement can be made. With both switches 920 and 940 on, a bipolar measurement can be made. For example, when the first switch 920 is on, and the second switch is off, the resultant functionality corresponds to that of FIG. 6A, albeit achieved with a different circuit topology. In this example, current flows from the impedance module 400 along the current input lead 320 , through the first switch 920 , and then to the first MX lead 180 . From there, the current proceeds to the multiplexer 160 .
- the resultant functionality corresponds to that of FIG. 6B.
- current from the impedance module 400 travels along the current input lead 320 , across the second switch 940 , then jumps to the second MX lead 200 .
- Current is received along the third MX lead 220 , from where it jumps to the current output lead 340 via the second switch 940 .
- the voltage is measured between the first and fourth MX leads 180 and 240 with the use of the first and second voltage leads 360 and 380 .
- the first and second switches 920 and 940 are both on, which corresponds to FIG. 6C or 6 D. Precisely to which of these two figures this example corresponds is determined by the inhibit states of the multiplexer 160 . For example, if the inhibit states of both of the one-to-N/4 multiplexers 640 and 660 are on, then bipolar measurements are performed with the second set of N/2 electrodes.
- the controller switching unit 900 also includes an internal load switch 1080 that is connected to the internal load 840 .
- the controller switching unit 900 and the internal load 840 are used to test the system and to increase the measurement range, as described above.
Abstract
A system and method for diagnosing the possibility of disease in a body part is described. The system includes an electrode array containing a plurality of electrodes capable of being electrically coupled to the body part. A first measurement unit makes an electrode assessment measurement with the electrode array. An electrode assessment module determines whether the plurality of electrodes are suitably coupled to the body part based on the electrode assessment measurement. If there is suitable coupling, a second measurement unit makes a diagnosis measurement with the electrode array. An electrical property module obtains an electrical property of the body part, such as impedance, based on the diagnosis measurement. A diagnosis module diagnoses the possibility of disease based on the measured electrical property.
Description
- This application claims priority from provisional application Ser. No. 60/429,316 filed Nov. 27, 2002.
- This invention relates to medical diagnosis of disease and specifically relates to diagnosis of disease using electrical impedances of body parts.
- The onset of disease is often accompanied by physical changes in a body part. Some physical changes, while not discernible by a patient, can be detected with appropriate diagnostic equipment, often at a relatively early stage of the disease. For example, the electrical impedance of a human breast can have diagnostic value.
- Electrical impedances of various body tissues are well known through studies on intact humans or from excised tissue made available following therapeutic surgical procedures. In addition, it is well documented that a decrease in electrical impedance occurs in tissue as it undergoes cancerous changes. This finding is consistent over many animal species and tissue types, including, for example human breast cancers.
- There have been a number of reports of attempts to detect breast tumors using electrical impedance imaging, such as, for example, U.S. Pat. No. 4,486,835. However, image fidelity and resolution can suffer when simplifying assumptions are made in mathematical models used to construct an image from impedance data.
- Despite such difficulties, a method that permits comparisons of electrical properties for diagnostic purposes has been developed that involves homologous body parts, i.e., body parts that are substantially similar, such as a left breast and a right breast. In this method, the impedance of a body part of a patient is compared to the impedance of the homologous body part of the same patient. One technique for screening and diagnosing diseased states within the body using electrical impedance is disclosed in U.S. Pat. No. 6,122,544, which is incorporated herein by reference. In this patent, data are obtained from two anatomically homologous body regions, one of which may be affected by disease. Differences in the electrical properties of the two homologous body parts could signal disease.
- Published international patent application, PCT/CA01/01788, which is incorporated herein by reference, discloses a breast electrode array for diagnosing the presence of a disease state in a living organism, wherein the electrode array comprises a flexible body, a plurality of flexible arms extending from the body, and a plurality of electrodes provided by the plurality of flexible arms, wherein the electrodes are arranged on the arms to obtain impedance measurements between respective electrodes. In one embodiment, the plurality of flexible arms are spaced around the flexible body and are provided with electrode pairs, which can be used to make tetrapolar impedance measurements.
- Tetrapolar impedance measurements are associated with injecting current between so called current injection electrodes and measuring a voltage drop between associated electrodes. In a preferred embodiment, the differences between corresponding homologous impedance measurements in the two body parts are compared in a variety of ways that allows the calculation of metrics that can serve either as an indicator of the presence of disease or to localize the disease to a specific breast quadrant or sector.
- Despite the attractive features of this method of diagnosing disease in one of a homologous pair of body parts, there are some problems associated with this straightforward implementation. In particular, some impedances obtained from electrical measurements may be spurious because of systematic errors occurring therein. Spurious impedances can lead to a faulty diagnosis. Therefore, any test that can be performed at the outset to test and correct for such error would increase diagnostic accuracy.
- To determine the impedance of a body part, such as a breast, for diagnostic purposes, several electrical measurements are performed with an electrode array having a plurality of electrodes in contact with the skin covering the underlying breast tissue. If one or more electrodes have lost contact with the skin, or if the contact with the skin is poor, errors can arise in the electrical measurements that then yield erroneous impedances.
- The present invention provides a method to determine both if there is electrode contact with the skin, and, if there is such contact, what the quality of that contact is. The method involves making bipolar measurements of the impedance.
- In an AC circuit, the impedance, Z, is a complex number, whose real part is the resistance R and whose imaginary part is the capacitive reactance XC=(ωC)−1, where ω is the frequency at which the voltage (and current) oscillates and C is the capacitance of the circuit. The magnitude of Z is given by
- |Z|=|V|/|I|,
- and the phase, φ, of Z is given by
- |φ|=|arg(V)−arg(I)|=|tan−1 [X C(ω)/R]|,
- where I denotes the current and V denotes the voltage.
- The phase associated with a body part of a patient at a particular frequency can be found by making bipolar measurements. By comparing the phase, at one or several frequencies, to expected values, a decision can be made as to whether the electrode is in suitable contact with the skin on the body part.
- Whereas impedance is most accurately measured using the tetrapolar method, bipolar measurement is better for determining adequacy of electrode-to-skin contact (herein referred to as either “contact” or “electrode contact”) because a poor contact result can be isolated to one or both electrodes. There are changes in both impedance magnitude and phase with deteriorating contact, but using phase instead of the magnitude is advantageous because a) impedance magnitude varies greatly from person to person, b) stray capacitance in the system can cause a smaller observed impedance value than would be expected from the high open-circuit value associated with a disconnected electrode, and c) sweat or some other substance could allow a low impedance to be registered even though the current traversing the skin is reduced because of poor electrode contact.
- Measuring the phase at different frequencies allows this measure to be even more precise because it can identify if excessive oil or other materials obstruct the skin-electrode interface. In the case of a multi-frequency contact assessment, the expected value for human skin at each of these frequencies is considered. With multiple frequencies, the measured ratio between measured impedance values at different frequencies can be compared to the expected values oh human skin.
- Described herein is a system and method for diagnosing the possibility of disease in a body part, such as a human breast. The system includes an electrode array containing a plurality of electrodes capable of being electrically coupled to the body part, and a first measurement unit for making an electrode assessment measurement for the electrode array. The system also includes an electrode assessment module for determining whether the plurality of electrodes are suitably coupled to the body part based on the electrode assessment measurement. The system further includes a second measurement unit for making a diagnosis measurement with the electrode array, and an electrical property module for obtaining an electrical property, such as electrical impedance, of the body part based on the diagnosis measurement. A diagnosis module utilizes the electrical property to diagnose the possibility of disease.
- In one embodiment, the plurality of electrodes includes a current injection electrode pair and an associated voltage measurement electrode pair that are applied to the body part. One current injection electrode of the current injection electrode pair and one proximal voltage measurement electrode of the voltage measurement electrode pair are used by the first measurement unit to make a bipolar measurement.
- The electrode assessment module can include a phase module for obtaining a phase, φ, from the bipolar measurement, whose absolute value is given by
- |φ|=|tan−1 [X C(ω)/R]|
- where XC(ω) is a capacitive reactance at an alternating frequency, ω, of a current injected during the bipolar measurement, and R is a resistance associated with the body part. The electrode assessment module may further include a contact module for determining that at least one of the current injection electrode and the voltage measurement electrode is not in electrical contact with the body part if the phase is outside a threshold range.
-
- where I is the current and V is a resultant voltage measured during the bipolar measurement, and a quality module for determining quality of electrical contact of the current injection electrode and the voltage measurement electrode with the body part based on the magnitude.
- In one embodiment, the electrode assessment module may include a) a phase module for obtaining a phase that is a function of a capacitive reactance, at a particular frequency, and a resistance, associated with the body part, and for obtaining other phases at other frequencies, and b) a contact module for determining that at least one of the current injection electrode and the voltage measurement electrode is not in electrical contact with the body part based on the phase at the particular frequency and the other phases at the other frequencies.
- The plurality of electrodes mentioned above can include nCI current injection electrode pairs and nCI associated voltage measurement electrode pairs that are applied to the body part. The second measurement unit injects a first current between a first pair of the nCI current injection electrode pairs, measures the resultant voltage difference V1 M between the voltage measurement electrode pair associated with the first current injection electrode pair, and repeats the preceding two steps of current injection and voltage difference measurement with the other electrode pairs until all nCI voltage differences, {V1 M, V2 M, . . . , Vn
CI M} are obtained. - In one embodiment, the electrical property module is an impedance module that uses the nCI voltage differences to obtain associated measured impedances, {Z1 M, Z2 M, . . . , Zn
CI M}, where Zj M is the measured impedance between the voltage electrodes associated with the jth current injection electrode pair. The system can then further include a diagnosis module for utilizing the measured impedances, {Z1 M, Z2 M, . . . , ZnCI M} to diagnose the possibility of disease. - In one embodiment, the system may also include a graphical user interface to indicate a status of the coupling between the plurality of electrodes and the body part.
- The present invention describes a system and/or method for measuring an electrical property, such as impedance, in a living tissue that includes an electrode array, first and second measurement units, an electrode assessment module, and an electrical property module, which are described in more detail below.
- FIG. 1 shows a block diagram of the system for diagnosing the possibility of disease, according to the teachings of the present invention;
- FIG. 2A shows the electrode array of FIG. 1.
- FIG. 2B shows a side view of a schematic of a particular current injection electrode pair and an associated voltage measurement electrode pair on the electrode array of FIG. 1.
- FIG. 3 shows the electrode assessment module of FIG. 1.
- FIG. 4 shows a graphical user interface (GUI) that illustrates the status of the skin-electrode contact, according to the teachings of the present invention.
- FIG. 5 shows a block diagram of a system for measuring a voltage in a body part, according to the teachings of the present invention.
- FIGS.6A-D shows modes of the controller switching unit of FIG. 5.
- FIG. 7 shows a hybrid mode of the controller switching unit of FIG. 5.
- FIG. 8 shows electrical connections in a particular tetrapolar impedance measurement that employs the system of FIG. 5.
- FIGS. 9A and 9B show the multiplexer of FIG. 5.
- FIG. 10 shows a diagnostic system that includes an internal load in addition to the components of FIG. 5.
- FIG. 11 shows one embodiment of the controller switching unit, according to the principles of the present invention.
- FIG. 1 shows a
system 100 for diagnosing the possibility of disease in a body part. Thesystem 100 includes anelectrode array 102 containing a plurality ofelectrodes 104 capable of being electrically coupled to the body part. Thesystem 100 also includes afirst measurement unit 106, anelectrode assessment module 108, asecond measurement unit 110, an electrical property module 112 and adiagnosis module 114. - The plurality of
electrodes 104 are applied to the body part to obtain an electrical property of the body part, such as impedance, to diagnose disease. - For this purpose, the plurality of
electrodes 104 have to be electrically connected to the body part. For example, adhesive means (not shown) can be used to connect theelectrodes 104 to the skin on the body part of a subject. The electrode conductive material, generally a hydrogel, can also have adhesive properties. The combined adhesive means can fail, resulting in an electrode that is not in proper electrical contact with the body part. To assess the adequacy of electrode coupling to the body part, thefirst measurement unit 106 utilizes theelectrode array 102 to make an electrode assessment measurement. Theelectrode assessment module 108 determines whether the plurality ofelectrodes 104 are adequately coupled to the body part based on the electrode assessment measurement, as described in more detail below. - If the
electrode assessment module 108 determines that the plurality of electrodes are suitably coupled to the body part, thesecond measurement unit 110 can then utilize theelectrode array 102 to make a diagnosis measurement. The electrical property module 112 obtains an electrical property of the body part, such as an impedance of the body part, based on the diagnosis measurement. Thediagnosis module 114 diagnoses the possibility of disease based on the electrical property. For example, cancer may change the impedance of the body part, a fact that can be exploited by thediagnosis module 114 to diagnose the possible presence of cancer. - FIG. 2A shows the
electrode array 102 of FIG. 1. Theelectrode array 102 includes the plurality ofelectrodes 104 that are applied to the body part. The plurality ofelectrodes 104 includecurrent injection electrodes 120 and voltage measurement electrodes 122 (two of these electrodes are labeled for simplicity). In general, there are ne current injection electrodes and ne voltage measurement electrodes in the electrode array 102 (in FIG. 2A, an example is shown with ne=12). Consequently, there are nCI=ne·(ne−1)/2 combinations of current injections, and an equal number of voltage measurements. - The
electrode array 102 contains several arms 123 (one arm is labeled for simplicity). Each arm includes a current injection electrode and a voltage measurement electrode. For example, thearm 125 includes a particularcurrent injection electrode 124 andvoltage measurement electrode 126. It is to be noted, however, that these electrodes can be physically identical and that the terms “current injection” and “voltage measurement” refer to their use during tetrapolar measurement, as used in this invention for the diagnosis stage. In addition, an inner pair of electrodes is provided on some of thearray arms 123. One particular inner set of electrodes 128 i and 130 i is located onarm 127. By positioning the inner set of electrodes partway on the array arms, these electrodes are placed closer to the nipple area of the breast, thus allowing better detection of cancers in the periareolar area of the breast. - For tetrapolar measurements, which are discussed below, current injection electrode pairs are used to send current through the body part, and voltage measurement electrode pairs are used to measure the resultant voltage. For example, FIG. 2B shows a side view of the particular
current injection electrode 124 and thevoltage measurement electrode 126 on thearm 125. Also shown in FIG. 2B is anotherarm 127 of theelectrode array 102 having anothercurrent injection electrode 128 andvoltage measurement electrode 130. - For bipolar measurements, however, a single electrode is used for both current injection and voltage measurement. For example, referring again to arm25 of FIG. 2B, current is injected between
electrodes electrodes electrode 124 into the body part, then is received from the body part throughelectrode 126. The resultant voltage difference betweenelectrodes voltmeter 131. Thefirst measurement unit 106 is used to make the bipolar impedance measurement betweenelectrodes arm 125 are suitably coupled to the body part before a tetrapolar measurement is performed to diagnose disease. - In FIG. 2B,
adjacent electrodes - FIG. 3 shows the
electrode assessment module 108 of FIG. 1. Theelectrode assessment module 108 includes aphase module 132, amagnitude module 134, acontact module 136 and aquality module 138. - The
phase module 132 obtains a phase φ from the bipolar measurement according to - |φ|=|tan−1 [X C(ω)/R]|
- The
contact module 136 uses the phase calculated by thephase module 132 to determine whether at least one of theelectrodes electrodes 124 and/or 126 fails to make adequate electrical contact with the skin. A useful index for this determination is the ratio XC/R, with XC/R<0.80 at 50 kHz indicating failed contact. For multiple frequencies, the relationship between the phases at each frequency is used to make the contact determination. Particularly, as frequency increases, the phase of the impedance reduces. If the measured phase at one frequency is larger than a measured phase at a lower frequency, something other than skin is making contact. -
- The
quality module 138 uses the magnitude |Z| calculated by themagnitude module 134 to determine the quality of the conductive hydrogel inelectrode 124 and/or 126. For example, as the electrodes are exposed to heat or air, the gel dries, decreasing its conductivity. This causes a significant increase in the magnitude of the bipolar impedance measured betweenelectrodes - Thus, the
first measurement unit 106 makes bipolar measurements that allow theelectrode assessment module 108 to determine a) whether theelectrodes electrodes - FIG. 4 shows a graphical user interface (GUI) that illustrates the status of the electrode-to-skin contact. A
display 150 shows tworepresentations electrode arrays 102, therepresentation 152 of the right breast array and therepresentation 154 of the left breast array. Each electrode array representation has twelve arms 156. In another embodiment, each electrode array representation has sixteen arms. The colour of thecircles 158 indicates which electrodes have been ascertained to be in contact with the skin. In one embodiment, a red circle indicates an inadequate contact, and a blue circle indicates an adequate one. Other indicators are possible, such as flashing circles representing inadequate contacts. For the purposes of explanation, white circles represent electrodes making adequate contact, and black circles represent those that are not. This determination is made by thecontact module 136. - The
quality module 138, furnishes its information at the bottom of the display. Here, abar 160 is shown with various levels of electrode quality with, in this example, three usable level—excellent, Good, and Pass—and one unacceptable level—Replace. If the quality is excellent, for example, then the word “Excellent” is highlighted on thebar 160. - Both electrode contact and quality information are made available to the user administering the diagnostic examination in real time. Thus, the user can take immediate steps to rectify a poor electrode-to-skin contact, or replace a deteriorated electrode, before proceeding with the diagnostic testing. The ability to display real time information is a direct result of using bipolar measurements for making the status determination. With bipolar measurements, one measurement relates to one electrode pair, and only the number of measurements as there air pairs is required to refresh the display. If tetrapolar measurements were used to make the contact determination, each measurement would include four electrodes and many sets of measurements per pair would be required to make the contact determination. Performing all of these measurements would take much longer.
- The
display 150 shown can be a computer or television monitor. In other embodiments, LED lights can signal electrode status. - If the results of the
electrode assessment module 108 indicate that the status of the plurality ofelectrodes 104 is suitable, then thesystem 100 can proceed to the diagnosis stage. Thesecond measurement unit 110 injects a first current between a first pair of the nCI current injection electrode pairs, and then measures the resultant voltage difference V1 M between a voltage measurement electrode pair. In a preferred embodiment, if current travels from a current injection electrode of a first arm to a current injection electrode of a second arm, then the voltage difference is measured between the voltage measurement electrodes of the same two arms. In FIG. 2B, for example, current can flow betweenelectrodes electrodes CI M} are obtained. - The impedance module112 uses the nCI voltage differences to obtain associated measured impedances, {Z1 M, Z2 M, . . . , Zn
C IM} where Zj M is the measured impedance between the voltage electrodes associated with the jth current injection electrode pair. - The
diagnosis module 114 utilizes the measured impedances, {Z1 M, Z2 M, . . . , ZnCI M} to diagnose the possibility of disease. For example, U.S. Pat. No. 6,122,544 describes a method that compares impedances between homologous body parts. In this method, the impedance of a body part of a patient is compared to the impedance of the homologous body part of the same patient. A difference between these two impedances could signal disease. - As described above, the
system 100 employs both tetrapolar and bipolar measurements to assess the quality of electrode contact. Adiagnostic system 1000 capable of both these types of measurements will now be described. - FIG. 5 shows a
system 1000 for measuring a voltage in abody part 110, such as a human breast. Thesystem 1000 includes N body leads 120. In what follows, the N body leads 120 are ordered from 1 to N for reference. Thesystem 1000 also includes a multiplexing unit 140 having amultiplexer 160, afirst MX lead 180, asecond MX lead 200, athird MX lead 220 and afourth MX lead 240. - The
system 1000 further includes acontroller switching unit 260 having afirst switch 280 connected to themultiplexer 160 by thefirst MX lead 180 and thesecond MX lead 200, asecond switch 300 connected to themultiplexer 160 by thethird MX lead 220 and thefourth MX lead 240, acurrent input lead 320 connected to thefirst switch 280, acurrent output lead 340 connected to thesecond switch 300, afirst voltage lead 360 connected to thefirst switch 280, and asecond voltage lead 380 connected to thesecond switch 300. Thecontroller switching unit 260 also includes acontroller 390. Thesystem 1000 further includes animpedance module 400 and adiagnosis module 420. - Also shown in FIG. 5 is an optional second set of
leads 440 that can be used when making measurements on a secondhomologous body part 460. The description below is directed mainly to an impedance measurement on the onebody part 110 with the set of N leads 120, but it should be understood that the discussion could be analogously expanded to include an impedance measurement on the secondhomologous body part 460 with the second set of leads 440. Thus, the principles of the present invention can be applied to diagnosis of disease by making electrical measurements on a single body part, or by making measurements on a homologous pair of body parts. When making measurements on only a single body part, the results can be compared to standard results obtained from population studies, for example, to diagnose disease. When using a homologous pair of body parts, the results of one body part can be compared to the results of the homologous body part of the same patient, as described in U.S. Pat. No. 6,122,544. - The N body leads120 electrically connect the multiplexing unit 140 to the
body part 110. Each of the N body leads 120 includes a wire capable of carrying a current and an electrode to attach to thebody part 110. A current conducting gel can act as an interface between the electrode and the skin covering thebody part 110. - The multiplexing unit140 and the
controller switching unit 260 allow a current to flow through thebody part 110 between any two body leads, n1 and n2, of the N body leads 120, and a resultant voltage to be measured between any two body leads, n3 and n4 of the N body leads 120, where n1≠n2 and n3 ≠n4, but where n1, n2, n3 and n4 need not otherwise be distinct. Thus, n1, n2, n3, and n4 are numbers belonging to the set {1, 2, . . . , N} that identify body leads. For example, if n1=7, then n1 denotes the seventh body lead from among the N body leads 120 used to inject current into thebody part 110. - The
impedance module 400 generates current that is injected into thecurrent input lead 320 and then delivered to the body part. Thecurrent output lead 340 receives the current from the body part. When the current is traveling through the body part, thefirst voltage lead 360 and thesecond voltage lead 380 are used to measure the resultant voltage between theseleads impedance module 400 uses this voltage, together with the known current injected into thecurrent input lead 320, to calculate a corresponding impedance, which may then be used by thediagnosis module 420 to diagnose disease. - In one embodiment, N is even and the
multiplexer 160 can electrically connect thefirst MX lead 180 and thefourth MX lead 240 to a first set of N/2 of the N leads, and thesecond MX lead 200 and thethird MX lead 220 to a second set of the other N/2 leads. In a conventional system, the first set of N/2 leads are exclusively used to inject current into and receive current from the body part. The second set of N/2 leads are then exclusively used to measure resultant voltages in tetrapolar measurements. This configuration limits the number of impedances that can be measured. - In the
system 1000, however, the second set of N/2 leads can also be used to inject and receive current, and the first set can be used to measure resultant voltages. Thus, thesystem 1000 can furnish a greater number of impedances. Moreover, as detailed below, the system can make both tetrapolar and bipolar measurements. The added benefits arise from the functionality of thecontroller switching unit 260. By using thecontroller switching unit 260, thesystem 1000 can force current to flow through thebody part 110 between any two body leads, n1 and n2, of the N body leads 120, and a resultant voltage to be measured between any two body leads, n3 and n4 of the N body leads 120, where n1≠n2 and n3 ≠n4. - FIGS.6A-D show several states of the
switches controller switching unit 260 of the system of FIG. 5. These states of theswitches controller 390. In FIG. 6A, current is injected into thefirst MX lead 180 and received by thefourth MX lead 240. While this current travels through thebody part 110, a resultant voltage is measured between thesecond MX lead 200 and thethird MX lead 220. This measurement is tetrapolar because current is forced to flow between two leads and the resultant voltage is measured between two other leads. - In FIG. 6B, current is injected into the
second MX lead 200 and received by thethird MX lead 220. The resultant voltage is measured between thefirst MX lead 180 and thefourth MX lead 240. This measurement is also tetrapolar. - In FIGS. 6A and 6B, the
first switch 280 and thesecond switch 300 are both in tetrapolar states since, for each of theswitches controller switching unit 260 is said to be in a tetrapolar mode. Thus, FIGS. 6A and 6B correspond to tetrapolar modes. - In a tetrapolar mode, the
current input lead 320 is electrically connected to exactly one of thefirst MX lead 180 and thesecond MX lead 200 and thefirst voltage lead 360 is electrically connected to the other one of thefirst MX lead 180 and thesecond MX lead 200; likewise, thecurrent output lead 340 is electrically connected to exactly one of thethird MX lead 220 and thefourth MX lead 240 and thesecond voltage lead 380 is connected to the other one of thethird MX lead 220 and thefourth MX lead 240. - The two tetrapolar modes shown in FIGS. 6A and 6B do not exhaust all the tetrapolar modes. For example, when the
first switch 280 state is the same as the state shown in FIG. 6A and thesecond switch 300 state is the same as the state shown in FIG. 6B, thecontroller switching unit 260 is also in a tetrapolar mode. Generally, thecontroller switching unit 260 is in a tetrapolar mode when n1, n2, n3 and n4 are distinct, where n1 and n2 are leads from among the N leads 120 used to inject current into and receive current from thebody part 110, and n3 and n4 are leads used to measure the resultant voltage. - In FIG. 6C, current is injected into the
first MX lead 180 and received by thefourth MX lead 240. While this current travels through thebody part 110, a resultant voltage is measured between thefirst MX lead 180 and thefourth MX lead 240. The second and third MX leads 200 and 220 are electrically unconnected to any of the N body leads 120 during this measurement. This measurement is bipolar because the pair of electrodes used for measuring a voltage is also used for current flow. - In FIG. 6D, current is injected into the
second MX lead 200 and received by thethird MX lead 220. The resultant voltage is measured between the same two leads 200 and 220. The first and fourth MX leads 180 and 240 are electrically unconnected during this measurement. This measurement is also bipolar. - In FIGS. 6C and 6D, the
first switch 280 and thesecond switch 300 are both in bipolar states since, for each of theswitches controller switching unit 260 is said to be in a bipolar mode. Thus, FIGS. 6C and 6D correspond to bipolar modes. - In a bipolar mode, the
current input lead 320 and thefirst voltage lead 360 are electrically connected to each other and to exactly one of thefirst MX lead 180 and thesecond MX lead 200, and thecurrent output lead 340 and thesecond voltage lead 380 are electrically connected to each other and to exactly one of thethird MX lead 220 and thefourth MX lead 240. - The two modes shown in FIGS. 6C and 6D do not exhaust all bipolar modes. For example, when the
first switch 280 state is the same as the state shown in FIG. 6C and thesecond switch 300 state is the same as the state shown in FIG. 6D, thecontroller switching unit 260 is also in a bipolar mode. More generally, thecontroller switching unit 260 is in a bipolar mode when n1=n3 or n4, and n2=n3 or n4, where n, and n2 are leads from among the N leads 120 used to inject and receive current, and n3 and n4 are leads used to measure the resultant voltage. - In addition to the tetrapolar and bipolar modes shown in FIGS. 6A-6D, there are also hybrid modes. FIG. 7 shows a hybrid mode of the
controller switching unit 260 of FIG. 5. Here, thefirst switch 280 is in a tetrapolar state and thesecond switch 300 is in a bipolar state. In a hybrid mode, n1≠n3 and n2=n4, or n1≠n4 and n2=n3, where again n1 and n2 are used for current flow and n3 and n4 are used for voltage measurement. - In FIG. 7, the lead n, is electrically connected to the
first MX lead 180 or to thefourth MX lead 240 via themultiplexer 160. The lead n2 is connected to whichever offirst MX lead 180 and thefourth MX lead 240 is not connected to the lead n1. The lead n3 is connected to thesecond MX lead 200 or thefourth MX lead 240, and the lead n4 is connected to whichever of thesecond MX lead 200 and thefourth MX lead 240 is not connected to the n3 lead. Thethird MX lead 220 is electrically unconnected during this hybrid measurement. - FIG. 8 shows electrical connections in a particular tetrapolar impedance measurement that employs the
system 1000 of FIG. 5. For simplicity, thesystem 1000 has only N=10 leads, and thecontroller 390, theimpedance module 400 and thediagnosis module 420 are not shown. In a different embodiment, N=32. Also not shown in the FIG. 8 is the second set of leads 440. The ten electrodes of the ten leads are shown: the first set of N/2=five electrodes 1-5 lie on the outside perimeter and the other set of five electrodes 6-10 lie on the inner perimeter. - All the electrodes 1-5 of the first set can be electrically connected to the first and fourth MX leads180 and 240, and all the electrodes 6-10 of the second set can be connected to the second and third MX leads 200 and 220 via the
multiplexer 160. In the example of FIG. 8, the connections shown are for one tetrapolar measurement in which n1=6, n2=9, n3=2 and n4=5, where electrode 60 is used to inject current into thebody part 110 and electrode 90 is used to receive the current. Theelectrodes 2 and 5 are used to measure the resultant voltage. Although all electrodes of the ten leads are shown in FIG. 8, only the four wires of the electrically active leads appear. - In particular, current is generated by the
impedance module 400 and sent to thecurrent input lead 320. From there, the current travels to thefirst MX lead 180 via thefirst switch 280 and from there to theelectrode 6 via themultiplexer 160. The current next travels through thebody part 110 to the electrode 9 and then through themultiplexer 160 to thefourth MX lead 240. The current then flows to thecurrent output lead 340 via thesecond switch 300 and then back to theimpedance module 400. The resultant voltage is measured between the first and second voltage leads 360 and 380, which corresponds to the voltage between theelectrodes 2 and 5. Thefirst voltage lead 360 is connected to theelectrode 2 via thefirst switch 280 and themultiplexer 160, and thesecond voltage lead 380 is electrically connected to the electrode 5 via thesecond switch 300 and themultiplexer 160. Thecontroller 390 controls the states of theswitches multiplexer 160 that determine through which leads current flows and which leads are used to measure voltage. - FIG. 9A shows the
multiplexer 160 of FIG. 5 in an embodiment in which a body part is being compared to a homologous body part. Themultiplexer 160 includes a first body part multiplexer 520 that includes a first body partA multiplexer unit 540 and a first body partB multiplexer unit 560. Themultiplexer 160 also includes a secondbody part multiplexer 580 that includes a second body partA multiplexer unit 600 and a second body partB multiplexer unit 620. The first body partA multiplexer unit 540 is connected to thefirst MX lead 180 and thefourth MX lead 240. The first body partB multiplexer unit 560 is connected to thesecond MX lead 200 and thethird MX lead 220. Although not shown in the interest of clarity, the second body partA multiplexer unit 600 is also connected to thefirst MX lead 180 and thefourth MX lead 240, and the second body partB multiplexer unit 620 is also connected to thesecond MX lead 200 and thethird MX lead 220. - The first body part multiplexer520 is used for multiplexing electrical signals to the first body part of the homologous pair. In particular, the first body part
A multiplexer unit 540 andB multiplexer unit 560 are both capable of multiplexing current and voltage signals to and from the N leads 120. Likewise, the secondbody part multiplexer 580 is used for multiplexing electrical signals to the homologous body part. In particular, the second body partA multiplexer unit 600 andB multiplexer unit 620 are both capable of multiplexing current and voltage signals to and from the N leads 120, as described below. - FIG. 9B shows the first body part
A multiplexer unit 540 of FIG. 9A. Themultiplexer unit 540 includes four one-to-N/4multiplexers multiplexer 640 to themultiplexer 680, and N/4 multiplexer current leads 740 connect themultiplexers leads multiplexers respective multiplexer leads multiplexer 640 is 1 (on) and the state of themultiplexer 660 is (0,0,0,1), where the first bit is for the inhibit state, and the last three bits identify which lead ofmultiplexer 660 is being activated, then current destined for the breast is directed to the tenth lead, provided the states of theswitches current input lead 320 to thefirst MX lead 180, as previously described. If the states of theswitches current input lead 320 to thefirst MX lead 180, but do connect thefirst voltage lead 360 to thefirst MX lead 180, then thislead 180, when themultiplexer 660 is in the state (0,0,0,1), measures the resultant voltage with the tenth lead. - A similar binary code for the
multiplexers switches current output lead 340 to thefourth MX lead 240. If thefourth MX lead 240 is not connected to thecurrent output lead 340, but is connected to thesecond voltage lead 220, then thefourth MX lead 240 is used for measuring the resultant voltage, provided the inhibit state of themultiplexer 680 or themultiplexer 700 is off. - The
B multiplexer unit 560 is similar to theA multiplexer unit 540 in that it has four one-to-N/4 multiplexers analogous to 640, 660, 680 and 700. However, the one-to-N/4 multiplexers are capable of connecting with the second and third MX leads 200 and 220, instead of the first and fourth MX leads 180 and 240. Here, the inhibit and control states determine which electrode from among the other N/2 electrodes is used to deliver current or measure voltage. - Thus, by setting inhibit and control states, in coordination with the states of the
switches - The inhibit and control states are set by the
controller 390 with a shift-register and/or a computer. A direct digital stream can be sent to the shift register for this purpose. - The function of the second
body part multiplexer 580 is analogous to that of the first body part multiplexer 520 and therefore need not be described further. - FIG. 10 shows a
diagnostic system 820 that includes aninternal load 840 in addition to the components described above in relation to FIG. 5. Theinternal load 840 is electrically connected to thefirst MX lead 180, thesecond MX lead 200, thethird MX lead 220 and thefourth MX lead 240. Theinternal load 840 is used for at least one of internal testing of thesystem 820 and varying the measurement range of thesystem 820. - Using the
first switch 280 and thesecond switch 300, theinternal load 840 can be connected to theimpedance module 400 in a tetrapolar mode or in a bipolar mode. Theinternal load 840 has a known impedance and therefore can be used to test thediagnostic system 820. - Additionally, the
internal load 840 can be used to change the measurement range of thesystem 820. By attaching thisinternal load 840 in parallel with any load, such as thebody part 110, thesystem 820 is capable of measuring larger impedances than would otherwise be possible. If the resistance of theinternal load 840 is Rint and is in parallel, the measured resistance R is given by - R=(1/R load+1/R int)−1
- where Rload is the resistance of the load. Consequently, the measured resistance is reduced from the value without the internal load, thereby increasing the measurement range of the
system 840. - The
switches controller switching unit 900 of FIG. 11 includes afirst switch 920 and asecond switch 940. Thecurrent input lead 320, thecurrent output lead 340, thefirst voltage lead 360 and thesecond voltage lead 380 split to connect to both the first andsecond switches - The
switches switches switches first switch 920 is on, and the second switch is off, the resultant functionality corresponds to that of FIG. 6A, albeit achieved with a different circuit topology. In this example, current flows from theimpedance module 400 along thecurrent input lead 320, through thefirst switch 920, and then to thefirst MX lead 180. From there, the current proceeds to themultiplexer 160. Current is received from themultiplexer 160 along the fourth MX lead, and delivered to thecurrent output lead 340 via thefirst switch 920. The resultant voltage is measured between the second and third MX leads 200 and 220 with the use of the first and second voltage leads 360 and 380. - In another example, when the
first switch 920 is off, and thesecond switch 940 is on, the resultant functionality corresponds to that of FIG. 6B. Here, current from theimpedance module 400 travels along thecurrent input lead 320, across thesecond switch 940, then jumps to thesecond MX lead 200. Current is received along thethird MX lead 220, from where it jumps to thecurrent output lead 340 via thesecond switch 940. The voltage is measured between the first and fourth MX leads 180 and 240 with the use of the first and second voltage leads 360 and 380. - In yet another example, the first and
second switches multiplexer 160. For example, if the inhibit states of both of the one-to-N/4multiplexers - The
controller switching unit 900 also includes an internal load switch 1080 that is connected to theinternal load 840. Thecontroller switching unit 900 and theinternal load 840 are used to test the system and to increase the measurement range, as described above. - It should be understood that various modifications could be made to the embodiments described and illustrated herein, without departing from the present invention, the scope of which is defined in the appended claims. The present invention involves the use of an electrode array for measuring impedances of a breast to determine the condition thereof. However, although emphasis has been placed on describing a system for diagnosing breast cancer, the principles of the present invention can also be advantageously applied to other diseases of other body parts.
Claims (24)
1. A method for diagnosing the possibility of disease in a body part, the method comprising
providing an electrode array containing a plurality of electrodes capable of being electrically coupled to the body part;
making an electrode assessment measurement with the electrode array;
determining whether the plurality of electrodes are suitably coupled to the body part based on the electrode assessment measurement;
making a diagnosis measurement with the electrode array;
obtaining an electrical property of the body part based on the diagnosis measurement; and
diagnosing the possibility of disease based on the electrical property of the body part.
2. The method of claim 1 , wherein the plurality of electrodes includes a current injection electrode pair and an associated voltage measurement electrode pair, the method further comprising, before the step of making an electrode assessment measurement,
applying the current injection electrode pair to the body part; and
applying the associated voltage measurement electrode pair to the body part.
3. The method of claim 2 , wherein the step of making an electrode assessment measurement includes utilizing one current injection electrode of the current injection electrode pair and one proximal voltage measurement electrode of the voltage measurement electrode pair to make a bipolar measurement.
4. The method of claim 3 , wherein the step of determining whether the plurality of electrodes are suitably coupled includes
computing a phase φ, whose absolute value is given by
|φ|=|tan−1 [X C(ω)/R]|
where XC(ω) is a capacitive reactance at an alternating frequency, ω, of a current injected during the bipolar measurement, and R is a resistance associated with the body part; and
if the phase is outside a threshold range, determining that at least one of the current injection electrode and the voltage measurement electrode is not in electrical contact with the body part.
5. The method of claim 4 , wherein the step of determining whether the plurality of electrodes are suitably coupled further includes
computing a magnitude Z given by
where I is the current and V is a resultant voltage measured during the bipolar measurement; and
determining quality of electrical contact of the current injection electrode and the voltage measurement electrode with the body part based on the magnitude.
6. The method of claim 3 , wherein the step of determining includes using a phase, which is a function of the capacitive reactance and the resistance, at a particular frequency, and other phases at other frequencies to establish that at least one of the current injection electrode and the voltage measurement electrode is not in electrical contact with the body part.
7. The method of claim 1 , wherein the plurality of electrodes includes nCI current injection electrode pairs, and nCI associated voltage measurement electrode pairs, where nCI is an integer greater than zero.
8. The method of claim 7 , wherein the step of making a diagnosis measurement includes
applying the nCI current injection electrode pairs on the body part; and
applying the nCI voltage measurement electrode pairs on the body part.
9. The method of claim 8 , wherein the step of making a diagnosis measurement further includes
injecting a first current between a first pair of the nCI current injection electrode pairs;
measuring the resultant voltage difference V1 M between the voltage measurement electrode pair associated with the first current injection electrode pair; and
repeating the preceding two steps of injecting and measuring with the other electrode pairs until all nCI voltage differences, {V1 M, V2 M, . . . , Vn CI M} are obtained.
10. The method of claim 9 , wherein the electrical property is impedance.
11. The method of claim 10 , wherein the step of obtaining includes using the nCI voltage differences to obtain associated measured impedances, {Z1 M, Z2 M, . . . , Zn C LM}, where Zj M is the measured impedance between the voltage electrodes associated with the jth current injection electrode pair.
12. The method of claim 1 , further comprising indicating a status of the coupling between the plurality of electrodes and the body part with a graphical user interface.
13. A system for diagnosing the possibility of disease in a body part, the system comprising
an electrode array containing a plurality of electrodes capable of being electrically coupled to the body part;
a first measurement unit for making an electrode assessment measurement with the electrode array;
an electrode assessment module for determining whether the plurality of electrodes are suitably coupled to the body part based on the electrode assessment measurement;
a second measurement unit for making a diagnosis measurement with the electrode array; and
an electrical property module for obtaining an electrical property of the body part based on the diagnosis measurement, wherein the electrical property is used to diagnose the possibility of disease.
14. The system of claim 13 , wherein the plurality of electrodes includes a current injection electrode pair and an associated voltage measurement electrode pair that are applied to the body part.
15. The system of claim 14 , wherein one current injection electrode of the current injection electrode pair and one proximal voltage measurement electrode of the voltage measurement electrode pair are used by the first measurement unit to make a bipolar measurement.
16. The system of claim 15 , wherein the electrode assessment module includes
a phase module for obtaining a phase, φ, from the bipolar measurement, whose absolute value is given by
|φ|=|tan−1 [X C(ω)/R]|
where XC(ω) is a capacitive reactance at an alternating frequency, ω, of a current injected during the bipolar measurement, and R is a resistance associated with the body part; and
a contact module for determining that at least one of the current injection electrode and the voltage measurement electrode is not in electrical contact with the body part if the phase is outside a threshold range.
17. The system of claim 16 , wherein the electrode assessment module includes
a magnitude module for computing a magnitude, Z, from the bipolar measurement, the magnitude given by
where I is the current and V is a resultant voltage measured during the bipolar measurement; and
a quality module for determining quality of electrical contact of the current injection electrode and the voltage measurement electrode with the body part based on the magnitude.
18. The system of claim 15 , wherein the electrode assessment module includes
a phase module for obtaining a phase that is a function of a capacitive reactance, at a particular frequency, and a resistance, associated with the body part, and for obtaining other phases at other frequencies; and
a contact module for determining that at least one of the current injection electrode and the voltage measurement electrode is not in electrical contact with the body part based on the phase at the particular frequency and the other phases at the other frequencies.
19. The system of claim 13 , wherein the plurality of electrodes includes nCI current injection electrode pairs and nCI associated voltage measurement electrode pairs that are applied to the body part.
20. The system of claim 19 , wherein the second measurement unit injects a first current between a first pair of the nCI current injection electrode pairs, measures the resultant voltage difference V1 M between the voltage measurement electrode pair associated with the first current injection electrode pair, and repeats the preceding two steps of current injection and voltage difference measurement with the other electrode pairs until all nCI voltage differences, {V1 M, V2 M, . . . , Vn CI M} are obtained.
21. The system of claim 20 , wherein the electrical property is impedance, and the electrical property module is an impedance module.
22. The system of claim 21 , wherein the impedance module uses the nCI voltage differences to obtain associated measured impedances, {Z1 M, Z2 M, . . . , Zn CI M}, where Zj M is the measured impedance between the voltage electrodes associated with the jth current injection electrode pair.
23. The system of claim 22 , further comprising a diagnosis module for utilizing the measured impedances, {Z1 M, Z2 M, . . . , Zn CI M} to diagnose the possibility of disease.
24. The system of claim 13 , further comprising a graphical user interface to indicate a status of the coupling between the plurality of electrodes and the body part.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/724,458 US20040243018A1 (en) | 2002-11-27 | 2003-11-28 | Apparatus and method for determining adequacy of electrode-to-skin contact and electrode quality for bioelectrical measurements |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US42931602P | 2002-11-27 | 2002-11-27 | |
US10/724,458 US20040243018A1 (en) | 2002-11-27 | 2003-11-28 | Apparatus and method for determining adequacy of electrode-to-skin contact and electrode quality for bioelectrical measurements |
Publications (1)
Publication Number | Publication Date |
---|---|
US20040243018A1 true US20040243018A1 (en) | 2004-12-02 |
Family
ID=32393539
Family Applications (4)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/722,511 Active 2025-06-25 US7457660B2 (en) | 2002-11-27 | 2003-11-28 | Eliminating interface artifact errors in bioimpedance measurements |
US10/722,508 Active 2024-10-06 US7212852B2 (en) | 2002-11-27 | 2003-11-28 | Bioimpedance measurement using controller-switched current injection and multiplexer selected electrode connection |
US10/724,458 Abandoned US20040243018A1 (en) | 2002-11-27 | 2003-11-28 | Apparatus and method for determining adequacy of electrode-to-skin contact and electrode quality for bioelectrical measurements |
US10/722,509 Abandoned US20040158167A1 (en) | 2002-11-27 | 2003-11-28 | Apparatus and method for performing impedance measurements |
Family Applications Before (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/722,511 Active 2025-06-25 US7457660B2 (en) | 2002-11-27 | 2003-11-28 | Eliminating interface artifact errors in bioimpedance measurements |
US10/722,508 Active 2024-10-06 US7212852B2 (en) | 2002-11-27 | 2003-11-28 | Bioimpedance measurement using controller-switched current injection and multiplexer selected electrode connection |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/722,509 Abandoned US20040158167A1 (en) | 2002-11-27 | 2003-11-28 | Apparatus and method for performing impedance measurements |
Country Status (5)
Country | Link |
---|---|
US (4) | US7457660B2 (en) |
EP (4) | EP1571982A1 (en) |
AU (4) | AU2003286049A1 (en) |
CA (4) | CA2450971A1 (en) |
WO (4) | WO2004047636A1 (en) |
Cited By (100)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2007067937A2 (en) * | 2005-12-06 | 2007-06-14 | St. Jude Medical, Atrial Figriliation Division, Inc. | Design of handle set for ablation catheter with indicators of catheter and tissue parameters |
US20080287788A1 (en) * | 2007-05-14 | 2008-11-20 | Lifescience Solutions, Llc | Systems and methods for organ monitoring |
US20090018418A1 (en) * | 2007-05-10 | 2009-01-15 | Glumetrics, Inc. | Equilibrium non-consuming fluorescence sensor for real time intravascular glucose measurement |
US20090105788A1 (en) * | 2007-10-18 | 2009-04-23 | Innovative Surgical Solutions, Llc | Minimally invasive nerve monitoring device and method |
US20090163904A1 (en) * | 2005-12-06 | 2009-06-25 | St. Jude Medical, Atrial Fibrillation Division, Inc. | System and Method for Assessing Coupling Between an Electrode and Tissue |
US20090264719A1 (en) * | 2008-04-17 | 2009-10-22 | Glumetrics, Inc. | Sensor for percutaneous intravascular deployment without an indwelling cannula |
US20090275827A1 (en) * | 2005-12-06 | 2009-11-05 | Aiken Robert D | System and method for assessing the proximity of an electrode to tissue in a body |
US20100036227A1 (en) * | 2007-11-26 | 2010-02-11 | C. R. Bard, Inc. | Apparatus and display methods relating to intravascular placement of a catheter |
US20100069921A1 (en) * | 2006-12-06 | 2010-03-18 | Miller Stephan P | System and method for assessing lesions in tissue |
US20100081949A1 (en) * | 2008-09-26 | 2010-04-01 | Derby Jr William J | Ecg lead-off detection using phase shift of recovered transthoracic impedance respiration signal |
US20100106047A1 (en) * | 2007-02-01 | 2010-04-29 | Ls Biopath, Inc. | Electrical methods for detection and characterization of abnormal tissue and cells |
US20100168735A1 (en) * | 2005-12-06 | 2010-07-01 | Don Curtis Deno | System and method for assessing coupling between an electrode and tissue |
US20100179436A1 (en) * | 2007-02-01 | 2010-07-15 | Moshe Sarfaty | Optical system for detection and characterization of abnormal tissue and cells |
US20100286690A1 (en) * | 2005-12-06 | 2010-11-11 | Saurav Paul | Assessment of electrode coupling for tissue ablation |
WO2011007147A1 (en) * | 2009-07-15 | 2011-01-20 | Wzvi Limited | Electrical impedance imaging |
US20110046505A1 (en) * | 2007-08-09 | 2011-02-24 | Impedimed Limited | Impedance measurement process |
US20110054344A1 (en) * | 2009-09-01 | 2011-03-03 | Slizynski Roman A | Use of impedance techniques in breast-mass detection |
US20110118727A1 (en) * | 2005-12-06 | 2011-05-19 | Fish Jeffrey M | System and method for assessing the formation of a lesion in tissue |
US20110230782A1 (en) * | 2007-10-18 | 2011-09-22 | Innovative Surgical Solutions, Llc | Neural monitoring sensor |
US20110230783A1 (en) * | 2007-10-18 | 2011-09-22 | Innovative Surgical Solutions, Llc | Neural event detection |
US20110237974A1 (en) * | 2007-10-18 | 2011-09-29 | Innovative Surgical Solutions, Llc | Neural monitoring system |
US8116841B2 (en) | 2007-09-14 | 2012-02-14 | Corventis, Inc. | Adherent device with multiple physiological sensors |
US20120065539A1 (en) * | 2009-09-01 | 2012-03-15 | Slizynski Roman A | Use of impedance techniques in breast-mass detection |
WO2012073239A2 (en) * | 2010-12-01 | 2012-06-07 | Yossi Gross | Techniques for use with a nail penetration device |
US8249686B2 (en) | 2007-09-14 | 2012-08-21 | Corventis, Inc. | Adherent device for sleep disordered breathing |
WO2012149471A2 (en) | 2011-04-28 | 2012-11-01 | Convergence Medical Devices | Devices and methods for evaluating tissue |
US8317783B2 (en) | 2005-12-06 | 2012-11-27 | St. Jude Medical, Atrial Fibrillation Division, Inc. | Assessment of electrode coupling for tissue ablation |
US8374688B2 (en) | 2007-09-14 | 2013-02-12 | Corventis, Inc. | System and methods for wireless body fluid monitoring |
US8412317B2 (en) | 2008-04-18 | 2013-04-02 | Corventis, Inc. | Method and apparatus to measure bioelectric impedance of patient tissue |
US8460189B2 (en) | 2007-09-14 | 2013-06-11 | Corventis, Inc. | Adherent cardiac monitor with advanced sensing capabilities |
US8535262B2 (en) | 2007-11-21 | 2013-09-17 | Glumetrics, Inc. | Use of an equilibrium intravascular sensor to achieve tight glycemic control |
US20130267821A1 (en) * | 2007-07-16 | 2013-10-10 | Dune Medical Devices Ltd. | Medical device and method for use in tissue characterization and treatment |
US8684925B2 (en) | 2007-09-14 | 2014-04-01 | Corventis, Inc. | Injectable device for physiological monitoring |
US8700115B2 (en) | 2009-11-04 | 2014-04-15 | Glumetrics, Inc. | Optical sensor configuration for ratiometric correction of glucose measurement |
US8718752B2 (en) | 2008-03-12 | 2014-05-06 | Corventis, Inc. | Heart failure decompensation prediction based on cardiac rhythm |
US8715589B2 (en) | 2009-09-30 | 2014-05-06 | Medtronic Minimed, Inc. | Sensors with thromboresistant coating |
US8784336B2 (en) | 2005-08-24 | 2014-07-22 | C. R. Bard, Inc. | Stylet apparatuses and methods of manufacture |
WO2014113672A1 (en) * | 2013-01-17 | 2014-07-24 | Cardioinsight Technologies, Inc. | Wave front detection for electrophysiological signals |
US8790259B2 (en) | 2009-10-22 | 2014-07-29 | Corventis, Inc. | Method and apparatus for remote detection and monitoring of functional chronotropic incompetence |
US8838195B2 (en) | 2007-02-06 | 2014-09-16 | Medtronic Minimed, Inc. | Optical systems and methods for ratiometric measurement of blood glucose concentration |
US8855822B2 (en) | 2012-03-23 | 2014-10-07 | Innovative Surgical Solutions, Llc | Robotic surgical system with mechanomyography feedback |
US8858455B2 (en) | 2006-10-23 | 2014-10-14 | Bard Access Systems, Inc. | Method of locating the tip of a central venous catheter |
US8892259B2 (en) | 2012-09-26 | 2014-11-18 | Innovative Surgical Solutions, LLC. | Robotic surgical system with mechanomyography feedback |
US8897868B2 (en) | 2007-09-14 | 2014-11-25 | Medtronic, Inc. | Medical device automatic start-up upon contact to patient tissue |
US8965498B2 (en) | 2010-04-05 | 2015-02-24 | Corventis, Inc. | Method and apparatus for personalized physiologic parameters |
US8983578B2 (en) | 2012-02-27 | 2015-03-17 | General Electric Company | System and method for transducer placement in soft-field tomography |
US8983593B2 (en) | 2011-11-10 | 2015-03-17 | Innovative Surgical Solutions, Llc | Method of assessing neural function |
US9039630B2 (en) | 2012-08-22 | 2015-05-26 | Innovative Surgical Solutions, Llc | Method of detecting a sacral nerve |
US9084550B1 (en) | 2007-10-18 | 2015-07-21 | Innovative Surgical Solutions, Llc | Minimally invasive nerve monitoring device and method |
US9125578B2 (en) | 2009-06-12 | 2015-09-08 | Bard Access Systems, Inc. | Apparatus and method for catheter navigation and tip location |
US9204927B2 (en) | 2009-05-13 | 2015-12-08 | St. Jude Medical, Atrial Fibrillation Division, Inc. | System and method for presenting information representative of lesion formation in tissue during an ablation procedure |
US9254163B2 (en) | 2005-12-06 | 2016-02-09 | St. Jude Medical, Atrial Fibrillation Division, Inc. | Assessment of electrode coupling for tissue ablation |
US9265443B2 (en) | 2006-10-23 | 2016-02-23 | Bard Access Systems, Inc. | Method of locating the tip of a central venous catheter |
US9301711B2 (en) | 2011-11-10 | 2016-04-05 | Innovative Surgical Solutions, Llc | System and method for assessing neural health |
US9339206B2 (en) | 2009-06-12 | 2016-05-17 | Bard Access Systems, Inc. | Adaptor for endovascular electrocardiography |
US9411936B2 (en) | 2007-09-14 | 2016-08-09 | Medtronic Monitoring, Inc. | Dynamic pairing of patients to data collection gateways |
US9415188B2 (en) | 2010-10-29 | 2016-08-16 | C. R. Bard, Inc. | Bioimpedance-assisted placement of a medical device |
US9445734B2 (en) | 2009-06-12 | 2016-09-20 | Bard Access Systems, Inc. | Devices and methods for endovascular electrography |
US9451897B2 (en) | 2009-12-14 | 2016-09-27 | Medtronic Monitoring, Inc. | Body adherent patch with electronics for physiologic monitoring |
US9456766B2 (en) | 2007-11-26 | 2016-10-04 | C. R. Bard, Inc. | Apparatus for use with needle insertion guidance system |
US9492226B2 (en) | 2005-12-06 | 2016-11-15 | St. Jude Medical, Atrial Fibrillation Division, Inc. | Graphical user interface for real-time RF lesion depth display |
US9492097B2 (en) | 2007-11-26 | 2016-11-15 | C. R. Bard, Inc. | Needle length determination and calibration for insertion guidance system |
US9521961B2 (en) | 2007-11-26 | 2016-12-20 | C. R. Bard, Inc. | Systems and methods for guiding a medical instrument |
US9526440B2 (en) | 2007-11-26 | 2016-12-27 | C.R. Bard, Inc. | System for placement of a catheter including a signal-generating stylet |
US9532724B2 (en) | 2009-06-12 | 2017-01-03 | Bard Access Systems, Inc. | Apparatus and method for catheter navigation using endovascular energy mapping |
US9554716B2 (en) | 2007-11-26 | 2017-01-31 | C. R. Bard, Inc. | Insertion guidance system for needles and medical components |
US9585593B2 (en) | 2009-11-18 | 2017-03-07 | Chung Shing Fan | Signal distribution for patient-electrode measurements |
US9615767B2 (en) | 2009-10-26 | 2017-04-11 | Impedimed Limited | Fluid level indicator determination |
US9622684B2 (en) | 2013-09-20 | 2017-04-18 | Innovative Surgical Solutions, Llc | Neural locating system |
US9636031B2 (en) | 2007-11-26 | 2017-05-02 | C.R. Bard, Inc. | Stylets for use with apparatus for intravascular placement of a catheter |
US9649048B2 (en) | 2007-11-26 | 2017-05-16 | C. R. Bard, Inc. | Systems and methods for breaching a sterile field for intravascular placement of a catheter |
US9681823B2 (en) | 2007-11-26 | 2017-06-20 | C. R. Bard, Inc. | Integrated system for intravascular placement of a catheter |
US20170219509A1 (en) * | 2016-02-03 | 2017-08-03 | Draeger Medical Systems, Inc. | Determining Electrophysiological Electrode Quality |
US9724012B2 (en) | 2005-10-11 | 2017-08-08 | Impedimed Limited | Hydration status monitoring |
US9757098B2 (en) | 2007-07-16 | 2017-09-12 | Dune Medical Devices Ltd. | Medical device and method for use in tissue characterization and treatment |
US9839372B2 (en) | 2014-02-06 | 2017-12-12 | C. R. Bard, Inc. | Systems and methods for guidance and placement of an intravascular device |
US9861293B2 (en) | 2011-04-28 | 2018-01-09 | Myolex Inc. | Sensors, including disposable sensors, for measuring tissue |
US9901362B2 (en) | 2007-07-16 | 2018-02-27 | Dune Medical Devices Ltd. | Medical device and method for use in tissue characterization and treatment |
US9901714B2 (en) | 2008-08-22 | 2018-02-27 | C. R. Bard, Inc. | Catheter assembly including ECG sensor and magnetic assemblies |
US9907513B2 (en) | 2008-10-07 | 2018-03-06 | Bard Access Systems, Inc. | Percutaneous magnetic gastrostomy |
US10046139B2 (en) | 2010-08-20 | 2018-08-14 | C. R. Bard, Inc. | Reconfirmation of ECG-assisted catheter tip placement |
US10307074B2 (en) | 2007-04-20 | 2019-06-04 | Impedimed Limited | Monitoring system and probe |
US10321833B2 (en) | 2016-10-05 | 2019-06-18 | Innovative Surgical Solutions. | Neural locating method |
US10349890B2 (en) | 2015-06-26 | 2019-07-16 | C. R. Bard, Inc. | Connector interface for ECG-based catheter positioning system |
US10449330B2 (en) | 2007-11-26 | 2019-10-22 | C. R. Bard, Inc. | Magnetic element-equipped needle assemblies |
US10478096B2 (en) | 2013-08-13 | 2019-11-19 | Innovative Surgical Solutions. | Neural event detection |
US10478097B2 (en) | 2013-08-13 | 2019-11-19 | Innovative Surgical Solutions | Neural event detection |
US10524691B2 (en) | 2007-11-26 | 2020-01-07 | C. R. Bard, Inc. | Needle assembly including an aligned magnetic element |
US10555685B2 (en) | 2007-12-28 | 2020-02-11 | St. Jude Medical, Atrial Fibrillation Division, Inc. | Method and apparatus for determining tissue morphology based on phase angle |
US10751509B2 (en) | 2007-11-26 | 2020-08-25 | C. R. Bard, Inc. | Iconic representations for guidance of an indwelling medical device |
US10870002B2 (en) | 2018-10-12 | 2020-12-22 | DePuy Synthes Products, Inc. | Neuromuscular sensing device with multi-sensor array |
US10869616B2 (en) | 2018-06-01 | 2020-12-22 | DePuy Synthes Products, Inc. | Neural event detection |
US10973584B2 (en) | 2015-01-19 | 2021-04-13 | Bard Access Systems, Inc. | Device and method for vascular access |
US10992079B2 (en) | 2018-10-16 | 2021-04-27 | Bard Access Systems, Inc. | Safety-equipped connection systems and methods thereof for establishing electrical connections |
US11000207B2 (en) | 2016-01-29 | 2021-05-11 | C. R. Bard, Inc. | Multiple coil system for tracking a medical device |
US11246505B2 (en) * | 2018-11-01 | 2022-02-15 | Biosense Webster (Israel) Ltd. | Using radiofrequency (RF) transmission system to find opening in tissue wall |
US11399777B2 (en) | 2019-09-27 | 2022-08-02 | DePuy Synthes Products, Inc. | Intraoperative neural monitoring system and method |
US11497438B2 (en) * | 2015-01-10 | 2022-11-15 | Deborah Dullen | Method and apparatus for the measurement of autonomic function for the diagnosis and validation of patient treatments and outcomes |
US11660013B2 (en) | 2005-07-01 | 2023-05-30 | Impedimed Limited | Monitoring system |
US11737678B2 (en) | 2005-07-01 | 2023-08-29 | Impedimed Limited | Monitoring system |
Families Citing this family (97)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AUPQ113799A0 (en) | 1999-06-22 | 1999-07-15 | University Of Queensland, The | A method and device for measuring lymphoedema |
JP4165879B2 (en) * | 2001-05-30 | 2008-10-15 | ピレリ・アンド・チ・ソチエタ・ペル・アツィオーニ | Method and apparatus for manufacturing glass optical fiber preform by vapor phase growth method |
WO2002100247A2 (en) * | 2001-06-13 | 2002-12-19 | Ckm Diagnostics, Inc. | Non-invasive method and apparatus for tissue detection |
US7596798B2 (en) * | 2003-06-16 | 2009-09-29 | Bertonis James G | Apparatus and method for extending DOCSIS cable modem service over wireless links |
DE10332820B4 (en) * | 2003-07-18 | 2006-07-20 | Osypka Medical Gmbh | Device for electrically converting a first voltage into a second voltage for measuring impedances and admittances on biological tissues |
WO2005122888A1 (en) | 2004-06-18 | 2005-12-29 | The University Of Queensland | Oedema detection |
US8068906B2 (en) | 2004-06-21 | 2011-11-29 | Aorora Technologies Pty Ltd | Cardiac monitoring system |
US7245961B2 (en) * | 2004-07-19 | 2007-07-17 | Hewlett-Packard Development Company, L.P. | ECG electrode characterization and compensation |
US20060085048A1 (en) * | 2004-10-20 | 2006-04-20 | Nervonix, Inc. | Algorithms for an active electrode, bioimpedance-based tissue discrimination system |
US7865236B2 (en) * | 2004-10-20 | 2011-01-04 | Nervonix, Inc. | Active electrode, bio-impedance based, tissue discrimination system and methods of use |
KR20060040500A (en) * | 2004-11-06 | 2006-05-10 | 삼성전자주식회사 | Method and appratus for measuring bio signal |
CA2528303A1 (en) | 2004-11-26 | 2006-05-26 | Z-Tech (Canada) Inc. | Weighted gradient method and system for diagnosing disease |
JP2006198334A (en) * | 2005-01-24 | 2006-08-03 | Tanita Corp | Bioelectrical impedance measuring device and body composition measuring apparatus |
EP2250963A3 (en) | 2005-07-01 | 2012-02-29 | Intersection Medical, Inc. | Pulmonary monitoring system |
DE102005031751B4 (en) * | 2005-07-07 | 2017-09-14 | Drägerwerk AG & Co. KGaA | Electroimpedance tomography device with common-mode signal suppression |
DE102005031752B4 (en) * | 2005-07-07 | 2017-11-02 | Drägerwerk AG & Co. KGaA | Electroimpedance tomography device with common-mode signal suppression |
CA2615845A1 (en) * | 2005-07-20 | 2007-01-25 | Impedance Cardiology Systems, Inc. | Index determination |
WO2007014417A1 (en) | 2005-08-02 | 2007-02-08 | Impedimed Limited | Impedance parameter values |
ATE383106T1 (en) | 2005-08-17 | 2008-01-15 | Osypka Medical Gmbh | DIGITAL DEMODULATION DEVICE AND METHOD FOR MEASURING ELECTRICAL BIOIMPEDANCE OR BIOADMITTANCE |
PL217421B1 (en) * | 2006-01-13 | 2014-07-31 | Stanisław Baj | A probe for the location of cancer tissues and method for the location of cancer tissues |
ES2545730T3 (en) | 2006-05-30 | 2015-09-15 | Impedimed Limited | Impedance measurements |
JP5241714B2 (en) | 2006-07-07 | 2013-07-17 | プロテウス デジタル ヘルス, インコーポレイテッド | Smart parenteral delivery system |
CN100421617C (en) * | 2006-08-16 | 2008-10-01 | 中山市创源电子有限公司 | Human body impedance measuring apparatus and fat meter using same |
FR2908281A1 (en) * | 2006-11-13 | 2008-05-16 | Softmed Technology | Electro interstitial scan device for e.g. non-invasive medical therapeutic control of human body, has controller processing intensity measurement to model human body and to visualize function of organs based on chromatology |
WO2008064426A1 (en) | 2006-11-30 | 2008-06-05 | Impedimed Limited | Measurement apparatus |
US7355416B1 (en) * | 2007-01-07 | 2008-04-08 | Microsemi Corp.- Analog Mixed Signal Group Ltd. | Measurement of cable quality by power over ethernet |
US7417443B2 (en) * | 2007-01-07 | 2008-08-26 | Microsemi Corp. - Analog Mixed Signal Group, Ltd. | Determination of effective resistance between a power sourcing equipment and a powered device |
EP2106241B1 (en) * | 2007-01-15 | 2015-05-06 | Impedimed Limited | Method for performing impedance measurements on a subject |
CA2703361C (en) | 2007-03-30 | 2016-06-28 | Impedimed Limited | Active guarding for reduction of resistive and capacitive signal loading with adjustable control of compensation level |
US9173585B2 (en) * | 2007-08-29 | 2015-11-03 | Cochlear Limited | Method and device for intracochlea impedance measurement |
US8251903B2 (en) * | 2007-10-25 | 2012-08-28 | Valencell, Inc. | Noninvasive physiological analysis using excitation-sensor modules and related devices and methods |
EP2211974A4 (en) | 2007-10-25 | 2013-02-27 | Proteus Digital Health Inc | Fluid transfer port information system |
CA2704061C (en) * | 2007-11-05 | 2017-06-20 | Impedimed Limited | Impedance determination |
US8419638B2 (en) | 2007-11-19 | 2013-04-16 | Proteus Digital Health, Inc. | Body-associated fluid transport structure evaluation devices |
US8022710B2 (en) * | 2008-01-18 | 2011-09-20 | GM Global Technology Operations LLC | Methods for common mode voltage-based AC fault detection, verification and/or identification |
US7649360B2 (en) * | 2008-01-18 | 2010-01-19 | Gm Global Technology Operations, Inc. | Apparatus and systems for common mode voltage-based AC fault detection, verification and/or identification |
US8010187B2 (en) * | 2008-01-25 | 2011-08-30 | The Trustees Of The Stevens Institute Of Technology | Three-dimensional impedance imaging device |
AU2008207672B2 (en) | 2008-02-15 | 2013-10-31 | Impedimed Limited | Impedance Analysis |
WO2009118727A1 (en) * | 2008-03-27 | 2009-10-01 | Microsemi Corp. - Analog Mixed Signal Group, Ltd. | Method and apparatus for detecting end of start up phase |
US8793091B2 (en) * | 2008-04-10 | 2014-07-29 | Nvidia Corporation | System and method for integrated circuit calibration |
WO2009147615A1 (en) * | 2008-06-06 | 2009-12-10 | Koninklijke Philips Electronics N.V. | Determining contact with a body |
CN102186414B (en) * | 2008-10-16 | 2013-09-11 | 皇家飞利浦电子股份有限公司 | Impedance measurement circuit and method |
AU2009321478B2 (en) * | 2008-11-28 | 2014-01-23 | Impedimed Limited | Impedance measurement process |
EE01061U1 (en) | 2009-02-12 | 2012-01-16 | JR Medical O� | Multichannel impedance cardiograph |
WO2010118476A1 (en) | 2009-04-16 | 2010-10-21 | Bivacor Pty Ltd | Heart pump controller |
US8632449B2 (en) | 2009-04-16 | 2014-01-21 | Bivacor Pty Ltd | Heart pump controller |
AU2011210648B2 (en) * | 2010-02-01 | 2014-10-16 | Otsuka Pharmaceutical Co., Ltd. | Data gathering system |
US8332020B2 (en) | 2010-02-01 | 2012-12-11 | Proteus Digital Health, Inc. | Two-wrist data gathering system |
US11213226B2 (en) * | 2010-10-07 | 2022-01-04 | Abbott Diabetes Care Inc. | Analyte monitoring devices and methods |
US20120330179A1 (en) * | 2011-06-24 | 2012-12-27 | Verathon, Inc. | Electrode contact-quality evaluation |
WO2013019494A2 (en) | 2011-08-02 | 2013-02-07 | Valencell, Inc. | Systems and methods for variable filter adjustment by heart rate metric feedback |
WO2013090798A1 (en) | 2011-12-14 | 2013-06-20 | Intersection Medical, Inc. | Devices, systems and methods for determining the relative spatial change in subsurface resistivities across frequencies in tissue |
TWI445951B (en) * | 2012-01-13 | 2014-07-21 | Univ Nat Chi Nan | Detection system and data processing device |
FR2994821B1 (en) * | 2012-08-28 | 2014-08-29 | Impeto Medical | IMPROVED ELECTROPHYSIOLOGICAL ANALYSIS SYSTEM |
US20150244189A1 (en) * | 2012-10-24 | 2015-08-27 | Sharp Kabushiki Kaisha | Balancer circuit and battery unit using same |
JP6178424B2 (en) * | 2012-11-14 | 2017-08-09 | ヴェクトリアス メディカル テクノロジーズ リミテッド | Drift compensation for embedded capacitance-based pressure transducers |
US8655427B1 (en) | 2012-11-29 | 2014-02-18 | Albert Einstein Healthcare Network | Catheter systems for measuring electrical properties of tissue and methods of use |
US20140276166A1 (en) * | 2013-03-13 | 2014-09-18 | Cardiologic Innovations Ltd | Method of measuring bioimpedance |
WO2014149061A1 (en) * | 2013-03-22 | 2014-09-25 | Ipgdx, Llc (Michigan Company) | Kalman algorithm electrical impedance device, and methods of making and using same |
DE102013205403A1 (en) * | 2013-03-27 | 2014-10-16 | Robert Bosch Gmbh | Method and device for detecting the state of hydration of a human or animal body |
US10194865B2 (en) | 2013-07-30 | 2019-02-05 | Emotiv, Inc. | Wearable system for detecting and measuring biosignals |
US11020182B1 (en) * | 2013-09-30 | 2021-06-01 | Michael Feloney | Tactile feedback for surgical robots |
ES2537351B1 (en) | 2013-11-04 | 2015-12-03 | Universidad De Sevilla | Intelligent bioimpedance sensor for biomedical applications |
WO2015131172A1 (en) * | 2014-02-28 | 2015-09-03 | Northeastern University | Instrumentation amplifier with digitally programmable input capacitance cancellation |
US9968301B2 (en) | 2014-07-09 | 2018-05-15 | The Board Of Regents, The University Of Texas System | Body-driven pseudorandom signal injection for biomedical acquisition channel calibration |
JP6194294B2 (en) * | 2014-08-28 | 2017-09-06 | 日立マクセル株式会社 | Motor function evaluation system and motor function measuring device |
FR3028744A1 (en) | 2014-11-25 | 2016-05-27 | Impeto Medical | ELECTROPHYSIOLOGICAL DATA COLLECTION DEVICE WITH INCREASED RELIABILITY |
KR102556074B1 (en) * | 2015-05-27 | 2023-07-17 | 조지아 테크 리서치 코오포레이션 | Wearable Technologies for Joint Health Assessment |
US10555686B1 (en) | 2015-07-01 | 2020-02-11 | Richard C. Kimoto | Removing parasitic effects from body impedance measurements with wrist-worn and/or other devices |
KR102556007B1 (en) * | 2015-10-07 | 2023-07-17 | 삼성전자주식회사 | Apparatus and method for measuring bio signal |
US10945618B2 (en) | 2015-10-23 | 2021-03-16 | Valencell, Inc. | Physiological monitoring devices and methods for noise reduction in physiological signals based on subject activity type |
WO2017070463A1 (en) | 2015-10-23 | 2017-04-27 | Valencell, Inc. | Physiological monitoring devices and methods that identify subject activity type |
EP3398237B1 (en) | 2015-12-30 | 2020-12-02 | Vectorious Medical Technologies Ltd. | Power-efficient pressure-sensor implant |
EP3400033A1 (en) | 2016-01-06 | 2018-11-14 | Bivacor Inc. | Heart pump with impeller axial position control |
US10966662B2 (en) | 2016-07-08 | 2021-04-06 | Valencell, Inc. | Motion-dependent averaging for physiological metric estimating systems and methods |
US10027447B2 (en) * | 2016-10-17 | 2018-07-17 | Analog Devices, Inc. | Circuits for on-situ differential impedance balance error measurement and correction |
TWI598073B (en) * | 2016-12-15 | 2017-09-11 | 財團法人工業技術研究院 | Physiological signal measuring method and physiological signal measuring device |
KR20180087043A (en) | 2017-01-24 | 2018-08-01 | 삼성전자주식회사 | Apparatus and method for measuring bioelectric impedance, Apparatus and method for measuring biometric information |
AU2018250273B2 (en) | 2017-04-05 | 2023-06-08 | Bivacor Inc. | Heart pump drive and bearing |
US10686414B2 (en) * | 2017-12-27 | 2020-06-16 | Mediatek Inc. | Load-adaptive class-G amplifier for low-power audio applications |
CN108853726B (en) * | 2018-05-09 | 2023-10-24 | 中国计量大学 | Special calibration system and method for electric needle therapeutic instrument |
US10686715B2 (en) | 2018-05-09 | 2020-06-16 | Biosig Technologies, Inc. | Apparatus and methods for removing a large-signal voltage offset from a biomedical signal |
US11047821B2 (en) * | 2018-05-31 | 2021-06-29 | Analog Devices International Unlimited Company | Bio-impedance and contact impedances measurement |
CN110151204A (en) * | 2019-06-23 | 2019-08-23 | 复旦大学 | Wearable non-intrusion type bladder capacity monitoring alarm |
CN111308206B (en) * | 2020-02-21 | 2022-04-15 | 苏州华兴源创科技股份有限公司 | Impedance detection device and detection method thereof |
TWI801878B (en) * | 2020-05-28 | 2023-05-11 | 台灣積體電路製造股份有限公司 | Impedance measurement device and system and method for determining impedances of devices under test |
CN111811829B (en) * | 2020-06-18 | 2022-10-28 | 深圳市周立功单片机有限公司 | Steering wheel hands-off detection device and method |
CN111722044B (en) * | 2020-06-29 | 2023-01-31 | 国网山东省电力公司营销服务中心(计量中心) | Direct current charging pile testing method, device and equipment based on frequency sweep calibration shunt |
US11272854B1 (en) | 2020-09-02 | 2022-03-15 | Analog Devices International Unlimited Company | Noise cancellation in impedance measurement circuits |
CN112505424B (en) * | 2020-11-30 | 2022-01-11 | 广东电网有限责任公司佛山供电局 | System and method for evaluating impact impedance distortion rate of vertical grounding electrode |
CN112505423B (en) * | 2020-11-30 | 2022-01-21 | 广东电网有限责任公司佛山供电局 | System and method for evaluating impact impedance distortion rate of horizontal grounding electrode |
EP4008248A1 (en) * | 2020-12-04 | 2022-06-08 | Stichting IMEC Nederland | A system and method for electrical impedance tomography of an object, and an impedance measurement unit |
WO2022130315A1 (en) * | 2020-12-18 | 2022-06-23 | Indian Institute Of Technology Kanpur | Data acquisition from sensor array |
US20220233230A1 (en) * | 2021-01-27 | 2022-07-28 | NovaScan, Inc. | Impedance-calibrated diagnostic medical devices |
CN114236221B (en) * | 2021-10-13 | 2023-09-26 | 北京华峰测控技术股份有限公司 | Differential voltage measurement circuit, device and method |
CN113899952B (en) * | 2021-10-26 | 2023-07-28 | 西安微电子技术研究所 | Automatic impedance testing system and method |
CN114859129B (en) * | 2022-07-07 | 2023-04-07 | 武汉地震工程研究院有限公司 | Wireless multi-channel micro impedance measurement method and device |
Citations (20)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3347223A (en) * | 1964-01-08 | 1967-10-17 | Universal Match Corp | Pneumograph |
US4416276A (en) * | 1981-10-26 | 1983-11-22 | Valleylab, Inc. | Adaptive, return electrode monitoring system |
US4486835A (en) * | 1981-05-13 | 1984-12-04 | Yeda Research And Development Co. Ltd. | Apparatus and techniques for electric tomography |
US5099844A (en) * | 1988-12-22 | 1992-03-31 | Biofield Corp. | Discriminant function analysis method and apparatus for disease diagnosis and screening |
US5146926A (en) * | 1990-10-26 | 1992-09-15 | Massachusetts Institute Of Technology | Method and apparatus for imaging electrical activity in a biological system |
US5184620A (en) * | 1991-12-26 | 1993-02-09 | Marquette Electronics, Inc. | Method of using a multiple electrode pad assembly |
US5196008A (en) * | 1989-09-07 | 1993-03-23 | Siemens Aktiengesellschaft | Method and circuit for monitoring electrode surfaces at the body tissue of a patient in an hf surgery device |
US5372141A (en) * | 1992-07-01 | 1994-12-13 | Body Composition Analyzers, Inc. | Body composition analyzer |
US5415164A (en) * | 1991-11-04 | 1995-05-16 | Biofield Corp. | Apparatus and method for screening and diagnosing trauma or disease in body tissues |
US5419337A (en) * | 1992-02-14 | 1995-05-30 | Dempsey; George J. | Non-invasive multi-electrocardiographic apparatus and method of assessing acute ischaemic damage |
US5788643A (en) * | 1997-04-22 | 1998-08-04 | Zymed Medical Instrumentation, Inc. | Process for monitoring patients with chronic congestive heart failure |
US5836990A (en) * | 1997-09-19 | 1998-11-17 | Medtronic, Inc. | Method and apparatus for determining electrode/tissue contact |
US5868670A (en) * | 1997-11-03 | 1999-02-09 | Werner A. Randell, Sr. | Article of manufacture for a biomedical electrode and indicator |
US5879308A (en) * | 1995-05-26 | 1999-03-09 | Instrumentarium Oy | Procedure for measuring a patient's impedance |
US6007532A (en) * | 1997-08-29 | 1999-12-28 | 3M Innovative Properties Company | Method and apparatus for detecting loss of contact of biomedical electrodes with patient skin |
US6122544A (en) * | 1998-05-01 | 2000-09-19 | Organ; Leslie William | Electrical impedance method and apparatus for detecting and diagnosing diseases |
US6171304B1 (en) * | 1997-04-04 | 2001-01-09 | 3M Innovative Properties Company | Method and apparatus for controlling contact of biomedical electrodes with patient skin |
US6391024B1 (en) * | 1999-06-17 | 2002-05-21 | Cardiac Pacemakers, Inc. | RF ablation apparatus and method having electrode/tissue contact assessment scheme and electrocardiogram filtering |
US6546270B1 (en) * | 2000-07-07 | 2003-04-08 | Biosense, Inc. | Multi-electrode catheter, system and method |
US6754517B2 (en) * | 2000-08-30 | 2004-06-22 | Polar Electro Oy | Apparatus for measuring an electrocardiograph signal |
Family Cites Families (28)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US93992A (en) * | 1869-08-24 | Improvement in oar-locks | ||
US3871359A (en) * | 1973-06-25 | 1975-03-18 | Interscience Technology Corp | Impedance measuring system |
US4184486A (en) * | 1977-08-11 | 1980-01-22 | Radelkis Elektrokemiai Muszergyarto Szovetkezet | Diagnostic method and sensor device for detecting lesions in body tissues |
IL53286A (en) * | 1977-11-02 | 1980-01-31 | Yeda Res & Dev | Apparatus and method for detection of tumors in tissue |
GB2131558B (en) * | 1982-11-05 | 1986-03-05 | Walter Farrer | Measuring potential difference |
US4646754A (en) * | 1985-02-19 | 1987-03-03 | Seale Joseph B | Non-invasive determination of mechanical characteristics in the body |
US4751471A (en) * | 1985-08-21 | 1988-06-14 | Spring Creek Institute, Inc. | Amplifying circuit particularly adapted for amplifying a biopotential input signal |
US5086781A (en) * | 1989-11-14 | 1992-02-11 | Bookspan Mark A | Bioelectric apparatus for monitoring body fluid compartments |
US5197479A (en) * | 1991-05-13 | 1993-03-30 | Mortara Instrument | Automatic electrode channel impedance measurement system for egg monitor |
GB2260416B (en) * | 1991-10-10 | 1995-07-26 | Smiths Industries Plc | Resistance monitors |
US5197467A (en) * | 1992-06-22 | 1993-03-30 | Telectronics Pacing Systems, Inc. | Multiple parameter rate-responsive cardiac stimulation apparatus |
WO1995020344A1 (en) * | 1994-01-28 | 1995-08-03 | Ep Technologies, Inc. | System for examining cardiac tissue electrical characteristics |
DE19514698C1 (en) * | 1995-04-13 | 1996-12-12 | Siemens Ag | Procedure for taking a distance measurement |
US5919142A (en) * | 1995-06-22 | 1999-07-06 | Btg International Limited | Electrical impedance tomography method and apparatus |
US5623938A (en) * | 1995-09-29 | 1997-04-29 | Siemens Medical Systems, Inc. | Method and apparatus for respiration monitoring |
US6393317B1 (en) * | 1997-02-24 | 2002-05-21 | Tanita Corporation | Living body impedance measuring instrument and body composition measuring instrument |
US6845264B1 (en) * | 1998-10-08 | 2005-01-18 | Victor Skladnev | Apparatus for recognizing tissue types |
US6317628B1 (en) * | 1999-01-25 | 2001-11-13 | Cardiac Pacemakers, Inc. | Cardiac rhythm management system with painless defribillation lead impedance measurement |
JP3907353B2 (en) * | 1999-08-26 | 2007-04-18 | 株式会社タニタ | Bioimpedance measurement device |
JP4401529B2 (en) * | 2000-04-10 | 2010-01-20 | パナソニック株式会社 | Laminate voltage measuring device |
WO2001087410A2 (en) * | 2000-05-15 | 2001-11-22 | Pacesetter, Inc. | Cardiac stimulation devices and methods for measuring impedances associated with the left side of the heart |
IL163684A0 (en) * | 2000-05-31 | 2005-12-18 | Given Imaging Ltd | Measurement of electrical characteristics of tissue |
US6768921B2 (en) * | 2000-12-28 | 2004-07-27 | Z-Tech (Canada) Inc. | Electrical impedance method and apparatus for detecting and diagnosing diseases |
DE10100569A1 (en) * | 2001-01-09 | 2002-07-11 | Koninkl Philips Electronics Nv | Driver circuit for display device |
US6684101B2 (en) * | 2001-04-25 | 2004-01-27 | Cardiac Pacemakers, Inc. | Implantable medical device employing single drive, dual sense impedance measuring |
AUPR571801A0 (en) * | 2001-06-15 | 2001-07-12 | Polartechnics Limited | Apparatus for tissue type recognition using multiple measurement techniques |
US6625487B2 (en) * | 2001-07-17 | 2003-09-23 | Koninklijke Philips Electronics N.V. | Bioelectrical impedance ECG measurement and defibrillator implementing same |
US6922586B2 (en) * | 2002-05-20 | 2005-07-26 | Richard J. Davies | Method and system for detecting electrophysiological changes in pre-cancerous and cancerous tissue |
-
2003
- 2003-11-27 CA CA002450971A patent/CA2450971A1/en not_active Abandoned
- 2003-11-27 EP EP03776723A patent/EP1571982A1/en not_active Withdrawn
- 2003-11-27 CA CA002451054A patent/CA2451054A1/en not_active Abandoned
- 2003-11-27 AU AU2003286049A patent/AU2003286049A1/en not_active Abandoned
- 2003-11-27 AU AU2003286046A patent/AU2003286046A1/en not_active Abandoned
- 2003-11-27 WO PCT/CA2003/001827 patent/WO2004047636A1/en not_active Application Discontinuation
- 2003-11-27 WO PCT/CA2003/001824 patent/WO2004048983A1/en not_active Application Discontinuation
- 2003-11-27 EP EP03776721A patent/EP1571981A2/en not_active Withdrawn
- 2003-11-27 WO PCT/CA2003/001825 patent/WO2004047627A2/en not_active Application Discontinuation
- 2003-11-27 AU AU2003286048A patent/AU2003286048A1/en not_active Abandoned
- 2003-11-27 AU AU2003286047A patent/AU2003286047A1/en not_active Abandoned
- 2003-11-27 CA CA2450968A patent/CA2450968C/en not_active Expired - Fee Related
- 2003-11-27 EP EP03776722A patent/EP1571996A1/en not_active Withdrawn
- 2003-11-27 WO PCT/CA2003/001826 patent/WO2004047643A1/en not_active Application Discontinuation
- 2003-11-27 CA CA2451059A patent/CA2451059C/en not_active Expired - Fee Related
- 2003-11-27 EP EP03776720A patent/EP1573343A1/en not_active Withdrawn
- 2003-11-28 US US10/722,511 patent/US7457660B2/en active Active
- 2003-11-28 US US10/722,508 patent/US7212852B2/en active Active
- 2003-11-28 US US10/724,458 patent/US20040243018A1/en not_active Abandoned
- 2003-11-28 US US10/722,509 patent/US20040158167A1/en not_active Abandoned
Patent Citations (20)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3347223A (en) * | 1964-01-08 | 1967-10-17 | Universal Match Corp | Pneumograph |
US4486835A (en) * | 1981-05-13 | 1984-12-04 | Yeda Research And Development Co. Ltd. | Apparatus and techniques for electric tomography |
US4416276A (en) * | 1981-10-26 | 1983-11-22 | Valleylab, Inc. | Adaptive, return electrode monitoring system |
US5099844A (en) * | 1988-12-22 | 1992-03-31 | Biofield Corp. | Discriminant function analysis method and apparatus for disease diagnosis and screening |
US5196008A (en) * | 1989-09-07 | 1993-03-23 | Siemens Aktiengesellschaft | Method and circuit for monitoring electrode surfaces at the body tissue of a patient in an hf surgery device |
US5146926A (en) * | 1990-10-26 | 1992-09-15 | Massachusetts Institute Of Technology | Method and apparatus for imaging electrical activity in a biological system |
US5415164A (en) * | 1991-11-04 | 1995-05-16 | Biofield Corp. | Apparatus and method for screening and diagnosing trauma or disease in body tissues |
US5184620A (en) * | 1991-12-26 | 1993-02-09 | Marquette Electronics, Inc. | Method of using a multiple electrode pad assembly |
US5419337A (en) * | 1992-02-14 | 1995-05-30 | Dempsey; George J. | Non-invasive multi-electrocardiographic apparatus and method of assessing acute ischaemic damage |
US5372141A (en) * | 1992-07-01 | 1994-12-13 | Body Composition Analyzers, Inc. | Body composition analyzer |
US5879308A (en) * | 1995-05-26 | 1999-03-09 | Instrumentarium Oy | Procedure for measuring a patient's impedance |
US6171304B1 (en) * | 1997-04-04 | 2001-01-09 | 3M Innovative Properties Company | Method and apparatus for controlling contact of biomedical electrodes with patient skin |
US5788643A (en) * | 1997-04-22 | 1998-08-04 | Zymed Medical Instrumentation, Inc. | Process for monitoring patients with chronic congestive heart failure |
US6007532A (en) * | 1997-08-29 | 1999-12-28 | 3M Innovative Properties Company | Method and apparatus for detecting loss of contact of biomedical electrodes with patient skin |
US5836990A (en) * | 1997-09-19 | 1998-11-17 | Medtronic, Inc. | Method and apparatus for determining electrode/tissue contact |
US5868670A (en) * | 1997-11-03 | 1999-02-09 | Werner A. Randell, Sr. | Article of manufacture for a biomedical electrode and indicator |
US6122544A (en) * | 1998-05-01 | 2000-09-19 | Organ; Leslie William | Electrical impedance method and apparatus for detecting and diagnosing diseases |
US6391024B1 (en) * | 1999-06-17 | 2002-05-21 | Cardiac Pacemakers, Inc. | RF ablation apparatus and method having electrode/tissue contact assessment scheme and electrocardiogram filtering |
US6546270B1 (en) * | 2000-07-07 | 2003-04-08 | Biosense, Inc. | Multi-electrode catheter, system and method |
US6754517B2 (en) * | 2000-08-30 | 2004-06-22 | Polar Electro Oy | Apparatus for measuring an electrocardiograph signal |
Cited By (203)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US11660013B2 (en) | 2005-07-01 | 2023-05-30 | Impedimed Limited | Monitoring system |
US11737678B2 (en) | 2005-07-01 | 2023-08-29 | Impedimed Limited | Monitoring system |
US8784336B2 (en) | 2005-08-24 | 2014-07-22 | C. R. Bard, Inc. | Stylet apparatuses and methods of manufacture |
US10004875B2 (en) | 2005-08-24 | 2018-06-26 | C. R. Bard, Inc. | Stylet apparatuses and methods of manufacture |
US11207496B2 (en) | 2005-08-24 | 2021-12-28 | C. R. Bard, Inc. | Stylet apparatuses and methods of manufacture |
US9724012B2 (en) | 2005-10-11 | 2017-08-08 | Impedimed Limited | Hydration status monitoring |
US11612332B2 (en) | 2005-10-11 | 2023-03-28 | Impedimed Limited | Hydration status monitoring |
US20090275827A1 (en) * | 2005-12-06 | 2009-11-05 | Aiken Robert D | System and method for assessing the proximity of an electrode to tissue in a body |
US8998890B2 (en) * | 2005-12-06 | 2015-04-07 | St. Jude Medical, Atrial Fibrillation Division, Inc. | Assessment of electrode coupling for tissue ablation |
US20080288038A1 (en) * | 2005-12-06 | 2008-11-20 | Saurav Paul | Method for Displaying Catheter Electrode-Tissue Contact in Electro-Anatomic Mapping and Navigation System |
US20090163904A1 (en) * | 2005-12-06 | 2009-06-25 | St. Jude Medical, Atrial Fibrillation Division, Inc. | System and Method for Assessing Coupling Between an Electrode and Tissue |
US11517372B2 (en) | 2005-12-06 | 2022-12-06 | St. Jude Medical, Atrial Fibrillation Division, Inc. | System and method for assessing lesions in tissue |
WO2007067937A2 (en) * | 2005-12-06 | 2007-06-14 | St. Jude Medical, Atrial Figriliation Division, Inc. | Design of handle set for ablation catheter with indicators of catheter and tissue parameters |
EP1962710A4 (en) * | 2005-12-06 | 2009-12-16 | St Jude Medical Atrial Fibrill | Method for displaying catheter electrode-tissue contact in electro-anatomic mapping and navigation system |
US20080281319A1 (en) * | 2005-12-06 | 2008-11-13 | Saurav Paul | Assessment of Electrode Coupling For Tissue Ablation |
US8406866B2 (en) | 2005-12-06 | 2013-03-26 | St. Jude Medical, Atrial Fibrillation Division, Inc. | System and method for assessing coupling between an electrode and tissue |
US10362959B2 (en) * | 2005-12-06 | 2019-07-30 | St. Jude Medical, Atrial Fibrillation Division, Inc. | System and method for assessing the proximity of an electrode to tissue in a body |
US10201388B2 (en) | 2005-12-06 | 2019-02-12 | St. Jude Medical, Atrial Fibrillation Division, Inc. | Graphical user interface for real-time RF lesion depth display |
US20100168735A1 (en) * | 2005-12-06 | 2010-07-01 | Don Curtis Deno | System and method for assessing coupling between an electrode and tissue |
US10182860B2 (en) | 2005-12-06 | 2019-01-22 | St. Jude Medical, Atrial Fibrillation Division, Inc. | Assessment of electrode coupling for tissue ablation |
US20100241117A1 (en) * | 2005-12-06 | 2010-09-23 | Saurav Paul | Assessment of Electrode Coupling for Tissue Ablation |
US20100286690A1 (en) * | 2005-12-06 | 2010-11-11 | Saurav Paul | Assessment of electrode coupling for tissue ablation |
US20080275465A1 (en) * | 2005-12-06 | 2008-11-06 | Saurav Paul | Design of Handle Set for Ablation Catheter with Indicators of Catheter and Tissue Parameters |
US8449535B2 (en) * | 2005-12-06 | 2013-05-28 | St. Jude Medical, Atrial Fibrillation Division, Inc. | System and method for assessing coupling between an electrode and tissue |
EP1962710A2 (en) * | 2005-12-06 | 2008-09-03 | St. Jude Medical, Atrial Fibrillation Division, Inc. | Method for displaying catheter electrode-tissue contact in electro-anatomic mapping and navigation system |
US20110118727A1 (en) * | 2005-12-06 | 2011-05-19 | Fish Jeffrey M | System and method for assessing the formation of a lesion in tissue |
US9610119B2 (en) | 2005-12-06 | 2017-04-04 | St. Jude Medical, Atrial Fibrillation Division, Inc. | System and method for assessing the formation of a lesion in tissue |
US9492226B2 (en) | 2005-12-06 | 2016-11-15 | St. Jude Medical, Atrial Fibrillation Division, Inc. | Graphical user interface for real-time RF lesion depth display |
US8603084B2 (en) | 2005-12-06 | 2013-12-10 | St. Jude Medical, Atrial Fibrillation Division, Inc. | System and method for assessing the formation of a lesion in tissue |
US9339325B2 (en) | 2005-12-06 | 2016-05-17 | St. Jude Medical, Atrial Fibrillation Division, Inc. | System and method for assessing lesions in tissue |
US9283026B2 (en) | 2005-12-06 | 2016-03-15 | St. Jude Medical, Atrial Fibrillation Division, Inc. | Assessment of electrode coupling for tissue ablation |
US9283025B2 (en) | 2005-12-06 | 2016-03-15 | St. Jude Medical, Atrial Fibrillation Division, Inc. | Assessment of electrode coupling for tissue ablation |
US9271782B2 (en) | 2005-12-06 | 2016-03-01 | St. Jude Medical, Atrial Fibrillation Division, Inc. | Assessment of electrode coupling of tissue ablation |
US8728077B2 (en) | 2005-12-06 | 2014-05-20 | St. Jude Medical, Atrial Fibrillation Division, Inc. | Handle set for ablation catheter with indicators of catheter and tissue parameters |
AU2006321570B2 (en) * | 2005-12-06 | 2012-08-02 | St. Jude Medical Atrial Fibrillation Division, Inc. | Method for displaying catheter electrode-tissue contact in electro-anatomic mapping and navigation system |
US9254163B2 (en) | 2005-12-06 | 2016-02-09 | St. Jude Medical, Atrial Fibrillation Division, Inc. | Assessment of electrode coupling for tissue ablation |
US9173586B2 (en) | 2005-12-06 | 2015-11-03 | St. Jude Medical, Atrial Fibrillation Division, Inc. | System and method for assessing coupling between an electrode and tissue |
US8267926B2 (en) | 2005-12-06 | 2012-09-18 | St. Jude Medical, Atrial Fibrillation Division, Inc. | Assessment of electrode coupling for tissue ablation |
US20080300589A1 (en) * | 2005-12-06 | 2008-12-04 | Saurav Paul | Assessment of Electrode Coupling for Tissue Ablation |
US8369922B2 (en) | 2005-12-06 | 2013-02-05 | St. Jude Medical Atrial Fibrillation Division, Inc. | Method for displaying catheter electrode-tissue contact in electro-anatomic mapping and navigation system |
US8317783B2 (en) | 2005-12-06 | 2012-11-27 | St. Jude Medical, Atrial Fibrillation Division, Inc. | Assessment of electrode coupling for tissue ablation |
WO2007067937A3 (en) * | 2005-12-06 | 2008-04-24 | St Jude Medical Atrial Fibrill | Design of handle set for ablation catheter with indicators of catheter and tissue parameters |
US8755860B2 (en) | 2005-12-06 | 2014-06-17 | St. Jude Medical, Atrial Fibrillation Division, Inc. | Method for displaying catheter electrode-tissue contact in electro-anatomic mapping and navigation system |
US8858455B2 (en) | 2006-10-23 | 2014-10-14 | Bard Access Systems, Inc. | Method of locating the tip of a central venous catheter |
US9265443B2 (en) | 2006-10-23 | 2016-02-23 | Bard Access Systems, Inc. | Method of locating the tip of a central venous catheter |
US9345422B2 (en) | 2006-10-23 | 2016-05-24 | Bard Acess Systems, Inc. | Method of locating the tip of a central venous catheter |
US9833169B2 (en) | 2006-10-23 | 2017-12-05 | Bard Access Systems, Inc. | Method of locating the tip of a central venous catheter |
US8403925B2 (en) | 2006-12-06 | 2013-03-26 | St. Jude Medical, Atrial Fibrillation Division, Inc. | System and method for assessing lesions in tissue |
US20100069921A1 (en) * | 2006-12-06 | 2010-03-18 | Miller Stephan P | System and method for assessing lesions in tissue |
US8437845B2 (en) * | 2007-02-01 | 2013-05-07 | Ls Biopath, Inc. | Electrical methods for detection and characterization of abnormal tissue and cells |
US20130230883A1 (en) * | 2007-02-01 | 2013-09-05 | Ls Biopath, Inc. | Methods for detection and characterization of abnormal tissue and cells using an electrical system |
US20100106047A1 (en) * | 2007-02-01 | 2010-04-29 | Ls Biopath, Inc. | Electrical methods for detection and characterization of abnormal tissue and cells |
US8865076B2 (en) * | 2007-02-01 | 2014-10-21 | Ls Biopath, Inc. | Methods for detection and characterization of abnormal tissue and cells using an electrical system |
US9566030B2 (en) | 2007-02-01 | 2017-02-14 | Ls Biopath, Inc. | Optical system for detection and characterization of abnormal tissue and cells |
US20100179436A1 (en) * | 2007-02-01 | 2010-07-15 | Moshe Sarfaty | Optical system for detection and characterization of abnormal tissue and cells |
US8417328B2 (en) | 2007-02-01 | 2013-04-09 | Ls Biopath, Inc. | Electrical systems for detection and characterization of abnormal tissue and cells |
US9839378B2 (en) | 2007-02-06 | 2017-12-12 | Medtronic Minimed, Inc. | Optical systems and methods for ratiometric measurement of blood glucose concentration |
US8838195B2 (en) | 2007-02-06 | 2014-09-16 | Medtronic Minimed, Inc. | Optical systems and methods for ratiometric measurement of blood glucose concentration |
US10307074B2 (en) | 2007-04-20 | 2019-06-04 | Impedimed Limited | Monitoring system and probe |
US8738107B2 (en) | 2007-05-10 | 2014-05-27 | Medtronic Minimed, Inc. | Equilibrium non-consuming fluorescence sensor for real time intravascular glucose measurement |
US20090018418A1 (en) * | 2007-05-10 | 2009-01-15 | Glumetrics, Inc. | Equilibrium non-consuming fluorescence sensor for real time intravascular glucose measurement |
US20080287788A1 (en) * | 2007-05-14 | 2008-11-20 | Lifescience Solutions, Llc | Systems and methods for organ monitoring |
US20130267821A1 (en) * | 2007-07-16 | 2013-10-10 | Dune Medical Devices Ltd. | Medical device and method for use in tissue characterization and treatment |
US9757098B2 (en) | 2007-07-16 | 2017-09-12 | Dune Medical Devices Ltd. | Medical device and method for use in tissue characterization and treatment |
US9901362B2 (en) | 2007-07-16 | 2018-02-27 | Dune Medical Devices Ltd. | Medical device and method for use in tissue characterization and treatment |
US9999353B2 (en) * | 2007-07-16 | 2018-06-19 | Dune Medical Devices Ltd. | Medical device and method for use in tissue characterization and treatment |
US20110046505A1 (en) * | 2007-08-09 | 2011-02-24 | Impedimed Limited | Impedance measurement process |
US20160089051A1 (en) * | 2007-08-09 | 2016-03-31 | Impedimed Limited | Impedance Measurement Process |
US10070800B2 (en) * | 2007-08-09 | 2018-09-11 | Impedimed Limited | Impedance measurement process |
US8684925B2 (en) | 2007-09-14 | 2014-04-01 | Corventis, Inc. | Injectable device for physiological monitoring |
US9411936B2 (en) | 2007-09-14 | 2016-08-09 | Medtronic Monitoring, Inc. | Dynamic pairing of patients to data collection gateways |
US8790257B2 (en) | 2007-09-14 | 2014-07-29 | Corventis, Inc. | Multi-sensor patient monitor to detect impending cardiac decompensation |
US8249686B2 (en) | 2007-09-14 | 2012-08-21 | Corventis, Inc. | Adherent device for sleep disordered breathing |
US8374688B2 (en) | 2007-09-14 | 2013-02-12 | Corventis, Inc. | System and methods for wireless body fluid monitoring |
US10599814B2 (en) | 2007-09-14 | 2020-03-24 | Medtronic Monitoring, Inc. | Dynamic pairing of patients to data collection gateways |
US10028699B2 (en) | 2007-09-14 | 2018-07-24 | Medtronic Monitoring, Inc. | Adherent device for sleep disordered breathing |
US8116841B2 (en) | 2007-09-14 | 2012-02-14 | Corventis, Inc. | Adherent device with multiple physiological sensors |
US9186089B2 (en) | 2007-09-14 | 2015-11-17 | Medtronic Monitoring, Inc. | Injectable physiological monitoring system |
US9579020B2 (en) | 2007-09-14 | 2017-02-28 | Medtronic Monitoring, Inc. | Adherent cardiac monitor with advanced sensing capabilities |
US9770182B2 (en) | 2007-09-14 | 2017-09-26 | Medtronic Monitoring, Inc. | Adherent device with multiple physiological sensors |
US8897868B2 (en) | 2007-09-14 | 2014-11-25 | Medtronic, Inc. | Medical device automatic start-up upon contact to patient tissue |
US8591430B2 (en) | 2007-09-14 | 2013-11-26 | Corventis, Inc. | Adherent device for respiratory monitoring |
US9538960B2 (en) | 2007-09-14 | 2017-01-10 | Medtronic Monitoring, Inc. | Injectable physiological monitoring system |
US8460189B2 (en) | 2007-09-14 | 2013-06-11 | Corventis, Inc. | Adherent cardiac monitor with advanced sensing capabilities |
US8285356B2 (en) | 2007-09-14 | 2012-10-09 | Corventis, Inc. | Adherent device with multiple physiological sensors |
US10405809B2 (en) | 2007-09-14 | 2019-09-10 | Medtronic Monitoring, Inc | Injectable device for physiological monitoring |
US8882679B2 (en) | 2007-10-18 | 2014-11-11 | Innovative Surgical Solutions, Llc | Neural monitoring system |
US20110237974A1 (en) * | 2007-10-18 | 2011-09-29 | Innovative Surgical Solutions, Llc | Neural monitoring system |
US8979767B2 (en) * | 2007-10-18 | 2015-03-17 | Innovative Surgical Solutions, Llc | Neural monitoring system |
US8517954B2 (en) * | 2007-10-18 | 2013-08-27 | Innovative Surgical Solutions, Llc | Neural monitoring system |
US20130072812A1 (en) * | 2007-10-18 | 2013-03-21 | Innovative Surgical Solutions, Llc | Neural monitoring system |
US8942797B2 (en) | 2007-10-18 | 2015-01-27 | Innovative Surgical Solutions, Llc | Neural monitoring system |
US9084550B1 (en) | 2007-10-18 | 2015-07-21 | Innovative Surgical Solutions, Llc | Minimally invasive nerve monitoring device and method |
US20110230782A1 (en) * | 2007-10-18 | 2011-09-22 | Innovative Surgical Solutions, Llc | Neural monitoring sensor |
US20130072811A1 (en) * | 2007-10-18 | 2013-03-21 | Innovative Surgical Solutions, Llc | Neural monitoring system |
US20110230783A1 (en) * | 2007-10-18 | 2011-09-22 | Innovative Surgical Solutions, Llc | Neural event detection |
US8343065B2 (en) * | 2007-10-18 | 2013-01-01 | Innovative Surgical Solutions, Llc | Neural event detection |
US8343079B2 (en) * | 2007-10-18 | 2013-01-01 | Innovative Surgical Solutions, Llc | Neural monitoring sensor |
US20090105788A1 (en) * | 2007-10-18 | 2009-04-23 | Innovative Surgical Solutions, Llc | Minimally invasive nerve monitoring device and method |
US8979790B2 (en) | 2007-11-21 | 2015-03-17 | Medtronic Minimed, Inc. | Use of an equilibrium sensor to monitor glucose concentration |
US8535262B2 (en) | 2007-11-21 | 2013-09-17 | Glumetrics, Inc. | Use of an equilibrium intravascular sensor to achieve tight glycemic control |
US10449330B2 (en) | 2007-11-26 | 2019-10-22 | C. R. Bard, Inc. | Magnetic element-equipped needle assemblies |
US10602958B2 (en) | 2007-11-26 | 2020-03-31 | C. R. Bard, Inc. | Systems and methods for guiding a medical instrument |
US11529070B2 (en) | 2007-11-26 | 2022-12-20 | C. R. Bard, Inc. | System and methods for guiding a medical instrument |
US10165962B2 (en) | 2007-11-26 | 2019-01-01 | C. R. Bard, Inc. | Integrated systems for intravascular placement of a catheter |
US10231753B2 (en) | 2007-11-26 | 2019-03-19 | C. R. Bard, Inc. | Insertion guidance system for needles and medical components |
US10751509B2 (en) | 2007-11-26 | 2020-08-25 | C. R. Bard, Inc. | Iconic representations for guidance of an indwelling medical device |
US11779240B2 (en) | 2007-11-26 | 2023-10-10 | C. R. Bard, Inc. | Systems and methods for breaching a sterile field for intravascular placement of a catheter |
US10849695B2 (en) | 2007-11-26 | 2020-12-01 | C. R. Bard, Inc. | Systems and methods for breaching a sterile field for intravascular placement of a catheter |
US10238418B2 (en) | 2007-11-26 | 2019-03-26 | C. R. Bard, Inc. | Apparatus for use with needle insertion guidance system |
US8849382B2 (en) * | 2007-11-26 | 2014-09-30 | C. R. Bard, Inc. | Apparatus and display methods relating to intravascular placement of a catheter |
US9999371B2 (en) | 2007-11-26 | 2018-06-19 | C. R. Bard, Inc. | Integrated system for intravascular placement of a catheter |
US10524691B2 (en) | 2007-11-26 | 2020-01-07 | C. R. Bard, Inc. | Needle assembly including an aligned magnetic element |
US9456766B2 (en) | 2007-11-26 | 2016-10-04 | C. R. Bard, Inc. | Apparatus for use with needle insertion guidance system |
US9681823B2 (en) | 2007-11-26 | 2017-06-20 | C. R. Bard, Inc. | Integrated system for intravascular placement of a catheter |
US9492097B2 (en) | 2007-11-26 | 2016-11-15 | C. R. Bard, Inc. | Needle length determination and calibration for insertion guidance system |
US9521961B2 (en) | 2007-11-26 | 2016-12-20 | C. R. Bard, Inc. | Systems and methods for guiding a medical instrument |
US9526440B2 (en) | 2007-11-26 | 2016-12-27 | C.R. Bard, Inc. | System for placement of a catheter including a signal-generating stylet |
US11707205B2 (en) | 2007-11-26 | 2023-07-25 | C. R. Bard, Inc. | Integrated system for intravascular placement of a catheter |
US10966630B2 (en) | 2007-11-26 | 2021-04-06 | C. R. Bard, Inc. | Integrated system for intravascular placement of a catheter |
US9549685B2 (en) | 2007-11-26 | 2017-01-24 | C. R. Bard, Inc. | Apparatus and display methods relating to intravascular placement of a catheter |
US9554716B2 (en) | 2007-11-26 | 2017-01-31 | C. R. Bard, Inc. | Insertion guidance system for needles and medical components |
US9649048B2 (en) | 2007-11-26 | 2017-05-16 | C. R. Bard, Inc. | Systems and methods for breaching a sterile field for intravascular placement of a catheter |
US11123099B2 (en) | 2007-11-26 | 2021-09-21 | C. R. Bard, Inc. | Apparatus for use with needle insertion guidance system |
US10105121B2 (en) | 2007-11-26 | 2018-10-23 | C. R. Bard, Inc. | System for placement of a catheter including a signal-generating stylet |
US11134915B2 (en) | 2007-11-26 | 2021-10-05 | C. R. Bard, Inc. | System for placement of a catheter including a signal-generating stylet |
US9636031B2 (en) | 2007-11-26 | 2017-05-02 | C.R. Bard, Inc. | Stylets for use with apparatus for intravascular placement of a catheter |
US10342575B2 (en) | 2007-11-26 | 2019-07-09 | C. R. Bard, Inc. | Apparatus for use with needle insertion guidance system |
US20100036227A1 (en) * | 2007-11-26 | 2010-02-11 | C. R. Bard, Inc. | Apparatus and display methods relating to intravascular placement of a catheter |
US10555685B2 (en) | 2007-12-28 | 2020-02-11 | St. Jude Medical, Atrial Fibrillation Division, Inc. | Method and apparatus for determining tissue morphology based on phase angle |
US8718752B2 (en) | 2008-03-12 | 2014-05-06 | Corventis, Inc. | Heart failure decompensation prediction based on cardiac rhythm |
US20090264719A1 (en) * | 2008-04-17 | 2009-10-22 | Glumetrics, Inc. | Sensor for percutaneous intravascular deployment without an indwelling cannula |
US8512245B2 (en) * | 2008-04-17 | 2013-08-20 | Glumetrics, Inc. | Sensor for percutaneous intravascular deployment without an indwelling cannula |
US8412317B2 (en) | 2008-04-18 | 2013-04-02 | Corventis, Inc. | Method and apparatus to measure bioelectric impedance of patient tissue |
US11027101B2 (en) | 2008-08-22 | 2021-06-08 | C. R. Bard, Inc. | Catheter assembly including ECG sensor and magnetic assemblies |
US9901714B2 (en) | 2008-08-22 | 2018-02-27 | C. R. Bard, Inc. | Catheter assembly including ECG sensor and magnetic assemblies |
US20100081949A1 (en) * | 2008-09-26 | 2010-04-01 | Derby Jr William J | Ecg lead-off detection using phase shift of recovered transthoracic impedance respiration signal |
US9907513B2 (en) | 2008-10-07 | 2018-03-06 | Bard Access Systems, Inc. | Percutaneous magnetic gastrostomy |
US10675086B2 (en) | 2009-05-13 | 2020-06-09 | St. Jude Medical, Atrial Fibrillation Division, Inc. | System and method for presenting information representative of lesion formation in tissue during an ablation procedure |
US9204927B2 (en) | 2009-05-13 | 2015-12-08 | St. Jude Medical, Atrial Fibrillation Division, Inc. | System and method for presenting information representative of lesion formation in tissue during an ablation procedure |
US10271762B2 (en) | 2009-06-12 | 2019-04-30 | Bard Access Systems, Inc. | Apparatus and method for catheter navigation using endovascular energy mapping |
US9532724B2 (en) | 2009-06-12 | 2017-01-03 | Bard Access Systems, Inc. | Apparatus and method for catheter navigation using endovascular energy mapping |
US10912488B2 (en) | 2009-06-12 | 2021-02-09 | Bard Access Systems, Inc. | Apparatus and method for catheter navigation and tip location |
US11419517B2 (en) | 2009-06-12 | 2022-08-23 | Bard Access Systems, Inc. | Apparatus and method for catheter navigation using endovascular energy mapping |
US9445734B2 (en) | 2009-06-12 | 2016-09-20 | Bard Access Systems, Inc. | Devices and methods for endovascular electrography |
US9125578B2 (en) | 2009-06-12 | 2015-09-08 | Bard Access Systems, Inc. | Apparatus and method for catheter navigation and tip location |
US9339206B2 (en) | 2009-06-12 | 2016-05-17 | Bard Access Systems, Inc. | Adaptor for endovascular electrocardiography |
US10231643B2 (en) | 2009-06-12 | 2019-03-19 | Bard Access Systems, Inc. | Apparatus and method for catheter navigation and tip location |
WO2011007147A1 (en) * | 2009-07-15 | 2011-01-20 | Wzvi Limited | Electrical impedance imaging |
US8928332B2 (en) | 2009-07-15 | 2015-01-06 | Wzvi Limited | Electrical impedance imaging |
CN102481113A (en) * | 2009-07-15 | 2012-05-30 | Wzvi有限公司 | Electrical impedance imaging |
US9037227B2 (en) * | 2009-09-01 | 2015-05-19 | Roman A. Slizynski | Use of impedance techniques in breast-mass detection |
US20110054344A1 (en) * | 2009-09-01 | 2011-03-03 | Slizynski Roman A | Use of impedance techniques in breast-mass detection |
US9042976B2 (en) * | 2009-09-01 | 2015-05-26 | Roman A. Slizynski | Use of impedance techniques in breast-mass detection |
US20110230784A2 (en) * | 2009-09-01 | 2011-09-22 | Roman Slizynski | Use of impedance techniques in breast-mass detection |
US20120065539A1 (en) * | 2009-09-01 | 2012-03-15 | Slizynski Roman A | Use of impedance techniques in breast-mass detection |
US8715589B2 (en) | 2009-09-30 | 2014-05-06 | Medtronic Minimed, Inc. | Sensors with thromboresistant coating |
US8790259B2 (en) | 2009-10-22 | 2014-07-29 | Corventis, Inc. | Method and apparatus for remote detection and monitoring of functional chronotropic incompetence |
US10779737B2 (en) | 2009-10-22 | 2020-09-22 | Medtronic Monitoring, Inc. | Method and apparatus for remote detection and monitoring of functional chronotropic incompetence |
US9615757B2 (en) | 2009-10-22 | 2017-04-11 | Medtronic Monitoring, Inc. | Method and apparatus for remote detection and monitoring of functional chronotropic incompetence |
US9615767B2 (en) | 2009-10-26 | 2017-04-11 | Impedimed Limited | Fluid level indicator determination |
US8700115B2 (en) | 2009-11-04 | 2014-04-15 | Glumetrics, Inc. | Optical sensor configuration for ratiometric correction of glucose measurement |
US9585593B2 (en) | 2009-11-18 | 2017-03-07 | Chung Shing Fan | Signal distribution for patient-electrode measurements |
US9451897B2 (en) | 2009-12-14 | 2016-09-27 | Medtronic Monitoring, Inc. | Body adherent patch with electronics for physiologic monitoring |
US9173615B2 (en) | 2010-04-05 | 2015-11-03 | Medtronic Monitoring, Inc. | Method and apparatus for personalized physiologic parameters |
US8965498B2 (en) | 2010-04-05 | 2015-02-24 | Corventis, Inc. | Method and apparatus for personalized physiologic parameters |
US10046139B2 (en) | 2010-08-20 | 2018-08-14 | C. R. Bard, Inc. | Reconfirmation of ECG-assisted catheter tip placement |
US9415188B2 (en) | 2010-10-29 | 2016-08-16 | C. R. Bard, Inc. | Bioimpedance-assisted placement of a medical device |
WO2012073239A2 (en) * | 2010-12-01 | 2012-06-07 | Yossi Gross | Techniques for use with a nail penetration device |
WO2012073239A3 (en) * | 2010-12-01 | 2012-09-13 | Yossi Gross | Techniques for use with a nail penetration device |
WO2012149471A2 (en) | 2011-04-28 | 2012-11-01 | Convergence Medical Devices | Devices and methods for evaluating tissue |
US11006849B2 (en) | 2011-04-28 | 2021-05-18 | Myolex Inc. | High performance sensors for electrical impedance myography |
US11246503B2 (en) | 2011-04-28 | 2022-02-15 | Myolex Inc. | Advanced electronic instrumentation for electrical impedance myography |
US8892198B2 (en) | 2011-04-28 | 2014-11-18 | Skulpt, Inc. | Devices and methods for evaluating tissue |
US9113808B2 (en) | 2011-04-28 | 2015-08-25 | Skulpt, Inc. | Systems, methods, and sensors for measuring tissue |
US9861293B2 (en) | 2011-04-28 | 2018-01-09 | Myolex Inc. | Sensors, including disposable sensors, for measuring tissue |
US8983593B2 (en) | 2011-11-10 | 2015-03-17 | Innovative Surgical Solutions, Llc | Method of assessing neural function |
US9301711B2 (en) | 2011-11-10 | 2016-04-05 | Innovative Surgical Solutions, Llc | System and method for assessing neural health |
US8983578B2 (en) | 2012-02-27 | 2015-03-17 | General Electric Company | System and method for transducer placement in soft-field tomography |
US8855822B2 (en) | 2012-03-23 | 2014-10-07 | Innovative Surgical Solutions, Llc | Robotic surgical system with mechanomyography feedback |
US9039630B2 (en) | 2012-08-22 | 2015-05-26 | Innovative Surgical Solutions, Llc | Method of detecting a sacral nerve |
US8892259B2 (en) | 2012-09-26 | 2014-11-18 | Innovative Surgical Solutions, LLC. | Robotic surgical system with mechanomyography feedback |
WO2014113672A1 (en) * | 2013-01-17 | 2014-07-24 | Cardioinsight Technologies, Inc. | Wave front detection for electrophysiological signals |
US10039464B2 (en) | 2013-01-17 | 2018-08-07 | Cardioinsight Technologies, Inc. | Phase values and wave front detection for electrophysiological cardiac signals |
US10478097B2 (en) | 2013-08-13 | 2019-11-19 | Innovative Surgical Solutions | Neural event detection |
US10478096B2 (en) | 2013-08-13 | 2019-11-19 | Innovative Surgical Solutions. | Neural event detection |
US9622684B2 (en) | 2013-09-20 | 2017-04-18 | Innovative Surgical Solutions, Llc | Neural locating system |
US9839372B2 (en) | 2014-02-06 | 2017-12-12 | C. R. Bard, Inc. | Systems and methods for guidance and placement of an intravascular device |
US10863920B2 (en) | 2014-02-06 | 2020-12-15 | C. R. Bard, Inc. | Systems and methods for guidance and placement of an intravascular device |
US11497438B2 (en) * | 2015-01-10 | 2022-11-15 | Deborah Dullen | Method and apparatus for the measurement of autonomic function for the diagnosis and validation of patient treatments and outcomes |
US10973584B2 (en) | 2015-01-19 | 2021-04-13 | Bard Access Systems, Inc. | Device and method for vascular access |
US10349890B2 (en) | 2015-06-26 | 2019-07-16 | C. R. Bard, Inc. | Connector interface for ECG-based catheter positioning system |
US11026630B2 (en) | 2015-06-26 | 2021-06-08 | C. R. Bard, Inc. | Connector interface for ECG-based catheter positioning system |
US11000207B2 (en) | 2016-01-29 | 2021-05-11 | C. R. Bard, Inc. | Multiple coil system for tracking a medical device |
US20170219509A1 (en) * | 2016-02-03 | 2017-08-03 | Draeger Medical Systems, Inc. | Determining Electrophysiological Electrode Quality |
CN107037084A (en) * | 2016-02-03 | 2017-08-11 | 德尔格医疗系统有限责任公司 | Determine electrophysiology electrode quality |
US10321833B2 (en) | 2016-10-05 | 2019-06-18 | Innovative Surgical Solutions. | Neural locating method |
US10869616B2 (en) | 2018-06-01 | 2020-12-22 | DePuy Synthes Products, Inc. | Neural event detection |
US10870002B2 (en) | 2018-10-12 | 2020-12-22 | DePuy Synthes Products, Inc. | Neuromuscular sensing device with multi-sensor array |
US11621518B2 (en) | 2018-10-16 | 2023-04-04 | Bard Access Systems, Inc. | Safety-equipped connection systems and methods thereof for establishing electrical connections |
US10992079B2 (en) | 2018-10-16 | 2021-04-27 | Bard Access Systems, Inc. | Safety-equipped connection systems and methods thereof for establishing electrical connections |
US11246505B2 (en) * | 2018-11-01 | 2022-02-15 | Biosense Webster (Israel) Ltd. | Using radiofrequency (RF) transmission system to find opening in tissue wall |
US11399777B2 (en) | 2019-09-27 | 2022-08-02 | DePuy Synthes Products, Inc. | Intraoperative neural monitoring system and method |
Also Published As
Publication number | Publication date |
---|---|
US20040171961A1 (en) | 2004-09-02 |
CA2450971A1 (en) | 2004-05-27 |
US20040181164A1 (en) | 2004-09-16 |
WO2004047636A1 (en) | 2004-06-10 |
AU2003286049A1 (en) | 2004-06-18 |
AU2003286047A1 (en) | 2004-06-18 |
CA2450968C (en) | 2014-01-07 |
EP1573343A1 (en) | 2005-09-14 |
WO2004047643A1 (en) | 2004-06-10 |
EP1571981A2 (en) | 2005-09-14 |
AU2003286046A1 (en) | 2004-06-18 |
CA2451054A1 (en) | 2004-05-27 |
WO2004047627A3 (en) | 2004-09-10 |
CA2451059C (en) | 2013-05-21 |
WO2004048983A1 (en) | 2004-06-10 |
US7212852B2 (en) | 2007-05-01 |
WO2004047627A2 (en) | 2004-06-10 |
CA2450968A1 (en) | 2004-05-27 |
CA2451059A1 (en) | 2004-05-27 |
US7457660B2 (en) | 2008-11-25 |
EP1571982A1 (en) | 2005-09-14 |
US20040158167A1 (en) | 2004-08-12 |
AU2003286048A1 (en) | 2004-06-18 |
EP1571996A1 (en) | 2005-09-14 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US20040243018A1 (en) | Apparatus and method for determining adequacy of electrode-to-skin contact and electrode quality for bioelectrical measurements | |
US10070800B2 (en) | Impedance measurement process | |
US6122544A (en) | Electrical impedance method and apparatus for detecting and diagnosing diseases | |
US8606353B2 (en) | Method, medium, and apparatus measuring biological signals using multi-electrode module, with a lead search | |
US10898100B2 (en) | Electrical impedance myography | |
US3971366A (en) | Apparatus and method for measuring the condition of the meridians and the corresponding internal organs of the living body | |
EP1180967B1 (en) | Electric mammograph | |
CA2615845A1 (en) | Index determination | |
EP1567052A2 (en) | Improved breast electrode array and method of analysis for detecting and diagnosing diseases | |
CA2231038C (en) | Electrical impedance method and apparatus for detecting and diagnosing diseases | |
US20080064979A1 (en) | System and method for prebalancing electrical properties to diagnose disease | |
US20080076998A1 (en) | Breast electrode array and method of analysis for detecting and diagnosing diseases | |
CN209847158U (en) | Electrical impedance imaging apparatus | |
US20080249432A1 (en) | Diagnosis of Disease By Determination of Elctrical Network Properties of a Body Part | |
US20220087593A1 (en) | Device for measuring a congestion of the digestive tract | |
RU66932U1 (en) | ELECTRIC IMPEDANCE COMPUTER MAMMOGRAPH | |
RU2204938C1 (en) | Method for regional bioimpedansometry | |
CA2492903C (en) | Electrical impedance method and apparatus for detecting and diagnosing diseases | |
Tang et al. | A portable 8-electrode EIT measurement system | |
Singh et al. | Smart & assistive electrical impedance tomographic tool for clinical imaging | |
WO2009005392A1 (en) | Electroimpedance computer mammograph | |
CN1024747C (en) | Electromagnetic diagnosis instrument for main and collateral channels maintaining biotic vitality |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: Z-TECH (CANADA) INC., CANADA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:ORGAN, LESLIE WILLIAM;SMITH, KENNETH CARLESS;IRONSTONE, JOEL STEVEN;REEL/FRAME:014720/0220 Effective date: 20040423 |
|
AS | Assignment |
Owner name: MMW FINANCIAL INC., CANADA Free format text: SECURITY INTEREST;ASSIGNOR:Z-TECH (CANADA) INC.;REEL/FRAME:017297/0585 Effective date: 20051228 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |