WO2000064335A1 - Wireless physiological monitor for magnetic resonance imaging - Google Patents

Wireless physiological monitor for magnetic resonance imaging Download PDF

Info

Publication number
WO2000064335A1
WO2000064335A1 PCT/US2000/008431 US0008431W WO0064335A1 WO 2000064335 A1 WO2000064335 A1 WO 2000064335A1 US 0008431 W US0008431 W US 0008431W WO 0064335 A1 WO0064335 A1 WO 0064335A1
Authority
WO
WIPO (PCT)
Prior art keywords
mri
non
ferrous
physiological data
mri scanner
Prior art date
Application number
PCT/US2000/008431
Other languages
French (fr)
Inventor
Patrick N. Morgan
Russell J. Iannuzzelli
Original Assignee
The Johns Hopkins University
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority to US13126199P priority Critical
Priority to US60/131,261 priority
Application filed by The Johns Hopkins University filed Critical The Johns Hopkins University
Publication of WO2000064335A1 publication Critical patent/WO2000064335A1/en

Links

Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00Arrangements or instruments for measuring magnetic variables
    • G01R33/20Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/28Details of apparatus provided for in groups G01R33/44 - G01R33/64
    • G01R33/32Excitation or detection systems, e.g. using radio frequency signals
    • G01R33/36Electrical details, e.g. matching or coupling of the coil to the receiver
    • G01R33/3692Electrical details, e.g. matching or coupling of the coil to the receiver involving signal transmission without using electrically conductive connections, e.g. wireless communication or optical communication of the MR signal or an auxiliary signal other than the MR signal
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00Arrangements or instruments for measuring magnetic variables
    • G01R33/20Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/44Arrangements or instruments for measuring magnetic variables involving magnetic resonance using nuclear magnetic resonance [NMR]
    • G01R33/48NMR imaging systems
    • G01R33/54Signal processing systems, e.g. using pulse sequences, Generation or control of pulse sequences ; Operator Console
    • G01R33/56Image enhancement or correction, e.g. subtraction or averaging techniques, e.g. improvement of signal-to-noise ratio and resolution
    • G01R33/567Image enhancement or correction, e.g. subtraction or averaging techniques, e.g. improvement of signal-to-noise ratio and resolution gated by physiological signals, i.e. synchronization of acquired MR data with periodical motion of an object of interest, e.g. monitoring or triggering system for cardiac or respiratory gating
    • G01R33/5673Gating or triggering based on a physiological signal other than an MR signal, e.g. ECG gating or motion monitoring using optical systems for monitoring the motion of a fiducial marker

Abstract

A wireless transmitter (180) is used in a physiological monitoring system for use with an MRI scanner (130). Sensor data corresponds cardiac data to respiratory motion data using a plurality of sensors on a patient (170).

Description

TITLE OF THE INVENTION

Wireless Physiological Monitor for Magnetic Resonance Imaging CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of earlier filed U.S. Provisional Application No. 60/131,261, filed April 27, 1999, which is incorporated herein in its entirety by reference.

FIELD OF THE INVENTION The present invention relates generally to a wireless physiological monitoring system that transmits patient data out of an MRI scanner without corrupting the data.

BACKGROUND OF THE INVENTION Magnetic Resonance Imaging (MRI) is a medical diagnostic technique that creates images of the body using nuclear magnetic resonance. A versatile, powerful, and sensitive tool, MRI can generate thin-section images of any part of the body from any angle, without surgical invasion and in a relatively short period of time. MRI gives biomedical and anatomical information that may allow early diagnosis of many diseases.

While undergoing MRI, a patient is placed in a cylindrical magnet that surrounds the body with a magnetic field. MRI next stimulates the body with radio waves and then "listens" to the body's electromagnetic transmissions. The transmitted signal is used to construct internal images of the body. The patient is placed in a magnetic field with a strength usually between 0.5 - 1.5 T. This field aligns the atoms with a magnetic moment, such as hydrogen atoms. The hydrogen atoms are then perturbed by an RF signal . As the atoms return to their equilibrium position, they emit their own RF signal, with a frequency that depends on the local magnetic field strength. By introducing variable gradients in the applied fields, and taking phase shifts in the signal into account, the hydrogen density within a particular volume can be reconstructed from the RF signals. The information obtained in this way is a measure of the amount of magnetization of the hydrogen in each volume element. This value differs for different types of tissues due to differences in the hydrogen density and its chemical bonds .

In current medical practice, MRI is preferred for diagnosing most diseases of the brain and central nervous system as well as having cardiac applications. MRI scanners also provide imaging supplementary to X-ray images because MRI can distinguish soft tissue in both normal and diseased states.

While MRI technology has seen many advancements in its twenty year history, there is room for improvement with respect to obtaining MRI data in a more efficient less cumbersome manner. Currently patients are required to be outfitted with several wires ending in leads positioned strategically about the body of the patient. Each wire is then routed out of the MRI tube to an information gathering device (typically a special purpose computer) . The number of leads, and therePfore wires is non-trivial and results in an arrangement that is time consuming to attach.

Hardwiring is used because an MRI environment is highly magnetic and does not lend itself to traditional modes of wireless transmission. Ferrous materials which are common to RF transmission devices are significantly affected by the strong magnetic fields associated with MRI . If a wireless physiological monitor could be developed, however, a simplified device attachable to a patient and containing a plurality of leads could be developed. Such a device would be easily attached to a patient saving a considerable amount of time and energy spent by both patient and staff.

What is needed is a wireless physiological monitor that includes multiple leads. Such a system would greatly reduce the amount of wiring attached to the patient resulting in more efficient and more accurate MRI gating algorithms and techniques .

SUMMARY OF THE INVENTION

The present invention comprises a wireless physiological monitor for use within an MRI scanner. Sensor data corresponding to cardiac and respiratory motion is gathered using a plurality of physiological sensors placed on the patient. The physiological sensor data is used to develop more accurate gating algorithms to compensate for patient motion during an MRI test. More accurate gating algorithms lead to better MRI images that have fewer and less significant image artifacts. The physiological sensors are connected to a wireless transmitter via sensor leads and wires. The wireless transmitter multiplexes the physiological sensor data into a single signal and transmits it out of the MRI scanner to a receiver still within the magnet room. The data is then relayed to a patch panel connecting the magnet room with the scanner electronics room where it is processed and interpreted accordingly.

The chief benefit of the present invention is the reduction of wiring required to monitor a patient. A wireless transmission system is employed to drastically reduce the amount of wiring required. The reduced wiring also reduces the time it takes to prepare a patient for an MRI test making the entire process more efficient. Moreover, the reduction in wiring provides an opportunity to use more physiological sensors in order to collect more data yielding more accurate motion data and better gating algorithms .

In accordance with a first embodiment of the invention is a wireless physiological monitoring system for use in an MRI magnet room. The system includes a plurality of sensors for acquiring and relaying physiological data. The sensors are attached to a patient undergoing an MRI test. A wireless transmitter, designed to be operable within an MRI scanner, receives physiological data from the sensors, multiplexes the acquired physiological data of each sensor into a multiplexed physiological data signal and transmits the multiplexed physiological data signal to a receiver outside the MRI scanner. The wireless transmitter is comprised of a non-ferrous casing and non-ferrous circuit components housed within the non-ferrous casing. The non-ferrous circuit components draw relatively low current in order to maximize the service time of the battery that provides the power for the transmitter. The circuit components also include an isolation circuit for countering the effects of magnetic fields present in the MRI scanner.

Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures.

BRIEF DESCRIPTION OF THE FIGURES FIGURE 1 illustrates a typical MRI environment that incorporates a wireless transmitter.

FIGURE 2 illustrates the functions of the wireless transmitter.

FIGURE 3 illustrates a wireless transmitter according to an embodiment of the present invention.

DETAILED DISCLOSURE OF THE INVENTION High quality images of the heart and coronary arteries obtained by magnetic resonance imaging (MRI) are adversely affected by motion. In order to minimize the resulting image artifacts, gating to the heart and respiratory cycle is required. Cardiac gating is a method used to synchronize the MRI test to a certain phase in the cardiac cycle of the patient. Similarly, respiratory gating is a method used to synchronize the MRI test to a certain phase in the respiratory cycle of the patient. In this way, the MRI test is only delivered during a reproducible period of time in which any motion of the patient is known and accounted for in the treatment thereby leading to results that are more accurate. Greater accuracy results from a reduction in image artifacts. Gating algorithms are used to determine the timing of the MRI test.

Typically, the heart cycle is monitored by an electrocardiograph (EKG) , which measures changes in electrical potential occurring during the heartbeat, and the respiratory cycle is monitored using a pressure transducer ("bellows") affixed around the abdomen. Use of a plurality of EKG leads, however, would improve system performance by providing more information with respect to heart position and motion. A plurality of leads necessitates multi-channel information gathering and subsequent transmission.

The present invention describes means for wirelessly transmitting multi-channel patient data acquired from a Data Acquisition System (DAS) from within a hostile MRI environment to a special purpose processing device for analysis. A Data Acquisition System (DAS) acquires data from multiple channels simultaneously. Multi-channel capability allows analysis of the data off-line for possible correlations and patterns among the various sensors and navigator MRI data. Forwarding acquired MRI data from the patient to specialized processors for analysis is no small task.

One of the problems with obtaining MRI data is the cumbersome nature of the equipment that is attached to a patient undergoing the MRI . The present invention significantly reduces the amount of wiring associated with MRI by converting the wires previously used to carry acquired MRI sensor data out of the MRI chamber to a wireless physiological monitor. FIGURE 1 shows a typical MRI environment. There is a magnet room 110 and a scanner electronics room 120. Magnet room 110 includes an MRI scanner 130. Scanner electronics room 120 includes a signal processor 140 and a computer 150. Magnet room 110 and scanner electronics room 120 are linked by a patch panel 160. Patch panel 160 receives a multiplexed data signal from a receiver 190 and passes it to signal processor 140 in scanner electronics room 120. Magnet room 110 is inundated with magnetic fields of varying strength. These fields are necessary to perform imaging but are incompatible with the electronics used to process and display MRI images. Therefore, magnet room 110 is shielded in isolation and patch panel 160 provides the only link between magnet room 110 and scanner electronics room 120. In a typical MRI environment a patient 170 lays on a table within MRI scanner 130. Multiple physiological sensors are attached to patient 170. These physiological sensors gather cardiac and respiratory motion data pertaining to the patient. Cardiac and respiratory motion occur naturally as patient 170 breathes and his or her heart beats. Such motion must be compensated for, however, in order to provide the clearest most accurate MRI images that have the least amount of image artifacts. Compensation is achieved by measuring patient motion and developing gating algorithms that compensate for the motion. Thus, when actual MRI data is processed, it is first filtered through a gating algorithm to remove as much noisy data as possible that could cause image artifacts to appear on the MRI image. Gating algorithms are developed based on cardiac and respiratory physiological sensor information.

It is axiomatic that the more accurate and plentiful patient motion data, the more accurate an MRI image will be. As mentioned earlier, cardiac and respiratory sensors are placed on patient 170 during MRI testing. Typically, these physiological sensors comprise sensor leads connected to wires. Prior to the present invention, the wires ran from patient 170 (within MRI scanner 130) to a physiological monitor (outside of MRI scanner 130 but still within magnet room 110) then to patch panel 160 before being fed to signal processor 140 in scanner electronics room 120. Such a configuration is clumsy, inefficient, and time consuming for the patient and MRI test administrator. The situation is exacerbated as the number of sensors increases .

A solution posed by the present invention is to wirelessly transmit multiplexed physiological sensor data from patient 170 to patch panel 160 via receiver 190. To do so requires a wireless transmitter 180 placed on or about patient 170 while inside MRI scanner 130. Wireless transmitter 180 must be capable of accepting all of the sensor leads as well as transmitting the acquired physiological sensor data out of MRI scanner 130. This is no easy task considering the high magnetic fields associated with magnet room 110 while an MRI test is in progress .

Once physiological sensor data is wirelessly transmitted out of MRI scanner 130 it is received by receiver 190. Receiver 190 would likely be attached to a wall in close proximity to patch panel 160. Once receiver 190 receives the multiplexed physiological sensor data it then forwards same to patch panel 160 via a shielded wire connection. An optically shielded connection between receiver 190 and patch panel 160 would likely provide the best shielding in magnet room 110.

The advantages of wireless transmission of physiological sensor data are clear. A device holding wireless transmitter 180 can easily be constructed to fit about patient 170. Multiple physiological sensors (analog or digital) can be attached (plugged into) wireless transmitter 180. The resulting decrease in wire lead lengths drastically reduces the cumbersome nature of the MRI test. The device can be put on by patient 170 prior to entry into MRI scanner 130 and the sensor leads can be positioned accordingly. The time required to prepare patient 170 for the MRI test can be significantly reduced. Moreover, the number of physiological sensors can be increased without a significant increase in wiring because the wire leads merely need to travel from their position on patient 170 to wireless transmitter 180. This is significant because an increase in physiological sensor data yields a better gating algorithm and, in turn, a more accurate MRI image .

FIGURE 2 illustrates the functions of the wireless transmitter. One of the chief benefits of using wireless technology is the ability to multiplex multiple data signals into a single information signal for transmission. The signal is de-multiplexed at some point downstream so that individual data signals can be processed. The electronics within wireless transmitter 180 are typical of most common RF transmitters from a functional standpoint. A plurality of signals (analog 205 and digital 210) are received into wireless transmitter 180. Analog signals 205 are initially multiplexed by a first multiplexer 215 before being converted to a digital signal by A/D converter 220. The multiplexed digitized signal is then fed to a second multiplexer 225. Second multiplexer 225 also receives sensor signals from the outside that are already in digital form. Second multiplexer 225 multiplexes the digitized multiplexed analog signals 205 and the digital signals 210 into a single digital signal that is then passed to a parallel to serial conversion circuitry 230. Once converted the signal is sent to a modulation and amplification stage. A frequency shift key modulator 235 operates on the signal under the guidance of a frequency controller 240. The modulated signal is then combined with an RF oscillation signal from an RF oscillator 245 and fed to an RF amplifier 250. The signal is amplified to the strength necessary to reach receiver 190. In a final step before transmission, the signal is filtered by a surface acoustic wave filter 255.

FIGURE 3 illustrates one possible implementation of wireless transmitter 180. Due to the high magnetic fields present in magnet room 110, special materials are used in the construction of wireless transmitter 180 in order for it to function within the hostile environment of MRI scanner 130.

The casing 300 of wireless transmitter 180 shields the electronics within as much as possible given the hostile environment of MRI scanner 130 and magnet room 110. Thus, non-ferrous materials make up casing 300 as well as the internal circuit components of wireless transmitter 180. In addition to using non-ferrous materials to shield the electronics of wireless transmitter 180, custom circuitry operating at specific frequencies is also employed to prevent, to the greatest extent possible, magnetic interference associated with MRI scanner 130 with respect to the transmission of patient sensor data.

The interior base of casing 300 includes a printed circuit board (PCB) 305. PCB 305 facilitates electrical connections between and among the various sub-modules that comprise the RF transmitter circuitry. Four sub-modules are shown including a battery 310, a power sub-module 315, a sensor sub-module 320, and an RF transmitter sub-module 325. Incoming sensor leads 330 connect to sensor lead connections 335. Sensor lead connections 335 connect to PCB 305 and PCB traces carry the physiological sensor signals to sensor sub-module 320 for pre-processing and multiplexing. The multiplexed sensor signal is then relayed via PCB 305 to RF transmitter sub-module 325 for signal modulation and amplification. Battery 305 provides the power necessary to drive the other circuitry while power sub-module 310 regulates the power to the other sub- modules and their circuitry. As previously mentioned, all components of wireless transmitter 180 are comprised of non-ferrous materials so that operation inside a huge magnetic field such as MRI scanner 130 is not substantially degraded or affected. The preferred modulation technique is an FSK type where the physiological sensor signals are sampled and their binary values are used to modulate between one of several different frequencies. A primary goal is to make the transmitter just powerful enough to transmit while keeping its current draw to a minimum. This allows the battery operated device to last a sufficient amount of time so that several MRI scan sessions can take place.

The two main system parameters for wireless transmitter 180 are available modulation bandwidth and average current draw. Shielding from gradient switching and isolation from the main MRI RF excitation source are paramount in establishing a robust design that works across a variety of MRI scans. To achieve sufficient shielding, a correctly layered set of different shielding materials is implemented for each internal component. Isolation refers to the ability to allow transmission in one direction while providing high isolation from energy (MRI scanner 130 in this case) in the reverse direction. Sufficient isolation is achieved with either a passive or an active isolation network.

In the following claims, any means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Therefore, it is to be understood that the foregoing is illustrative of the present invention and is not to be construed as limited to the specific embodiments disclosed, and that modifications to the disclosed embodiments, as well as other embodiments, are intended to be included within the scope of the appended claims. The invention is defined by the following claims, with equivalents of the claims to be included therein.

Claims

CLAIMS :
1. A wireless physiological monitoring system for use in an MRI magnet room comprising: a plurality of sensors for acquiring and relaying physiological data, said sensors capable of being operatively attached to a patient undergoing an MRI test, each of said sensors having a magnetically shielded lead length; a wireless transmitter operable within an MRI scanner for receiving each of said magnetically shielded lead lengths, multiplexing the acquired physiological data of each sensor into a multiplexed physiological data signal and transmitting the multiplexed physiological data signal; and a receiver within said magnet room for receiving the transmitted multiplexed physiological data signal.
2. A wireless physiological monitoring system operable within an MRI scanner and magnet room, said system comprising: means for obtaining physiological data; means for wirelessly transmitting obtained physiological data; and means for receiving transmitted physiological data.
3. A wireless transmitter operable within an MRI scanner comprising: a magnetically shielded non-ferrous casing; and non-ferrous circuitry housed within said non-ferrous casing, said non-ferrous circuitry for: receiving electrical signals representing physiological data; multiplexing said electrical signals representing physiological data creating a multiplexed physiological data signal; and wirelessly transmitting the multiplexed physiological data signal .
4. A wireless transmitter operable within an MRI scanner comprising: a non-ferrous casing; non-ferrous circuit components housed within said non- ferrous casing; and a battery, wherein said non-ferrous circuit components draw relatively low current in order to maximize the service time of said battery; and said circuit components include an isolation circuit for countering the effects of a magnetic field present in said MRI scanner.
5. A wireless transmitter operable within an MRI scanner comprising: non-ferrous casing materials; non-ferrous circuit components housed within said casing; circuit means for minimizing current draw to said non- ferrous circuit components; and circuit means for isolating a signal to be transmitted from magnetic fields associated with the MRI scanner.
PCT/US2000/008431 1999-04-27 2000-03-29 Wireless physiological monitor for magnetic resonance imaging WO2000064335A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US13126199P true 1999-04-27 1999-04-27
US60/131,261 1999-04-27

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
AU40496/00A AU4049600A (en) 1999-04-27 2000-03-29 Wireless physiological monitor for magnetic resonance imaging

Publications (1)

Publication Number Publication Date
WO2000064335A1 true WO2000064335A1 (en) 2000-11-02

Family

ID=22448658

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2000/008431 WO2000064335A1 (en) 1999-04-27 2000-03-29 Wireless physiological monitor for magnetic resonance imaging

Country Status (2)

Country Link
AU (1) AU4049600A (en)
WO (1) WO2000064335A1 (en)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ES2244273A1 (en) * 2003-02-14 2005-12-01 Universidad Complutense De Madrid Multi modal compatible versatile respirator for use on subjects e.g. small experimentation animals, has control module to operate electromagnetic valves in pneumatic module as well as regulate lung pressure and flow of gases into lungs
WO2005116676A1 (en) * 2004-05-25 2005-12-08 Hvidovre Hospital Encoding and transmission of signals as rf signals for detection using an mr apparatus
WO2006099010A1 (en) * 2005-03-09 2006-09-21 Invivo Corporation Patient supported in-bore monitor for mri
EP1773191A2 (en) * 2004-07-23 2007-04-18 Medrad, Inc. Wireless patient monitoring device for magnetic resonance imaging
WO2007134165A3 (en) * 2006-05-12 2008-12-31 Invivo Corp Method of transferring software and patient data in an mri wireless patient monitor system
DE102007045748A1 (en) * 2007-09-25 2009-04-09 Siemens Ag Adapter device for physiological signals and magnetic resonance apparatus with it
US9504429B1 (en) * 2012-06-28 2016-11-29 Fonar Corporation Apparatus for controlling the operation of an MRI system
US9660336B2 (en) 2013-02-07 2017-05-23 Kevan ANDERSON Systems, devices and methods for transmitting electrical signals through a faraday cage

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5511553A (en) * 1989-02-15 1996-04-30 Segalowitz; Jacob Device-system and method for monitoring multiple physiological parameters (MMPP) continuously and simultaneously
US5552708A (en) * 1993-11-30 1996-09-03 U.S. Philips Corporation Magnetic resonance imaging apparatus comprising a communication system
US5964705A (en) * 1997-08-22 1999-10-12 Image-Guided Drug Delivery System, Inc. MR-compatible medical devices
US6052614A (en) * 1997-09-12 2000-04-18 Magnetic Resonance Equipment Corp. Electrocardiograph sensor and sensor control system for use with magnetic resonance imaging machines

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5511553A (en) * 1989-02-15 1996-04-30 Segalowitz; Jacob Device-system and method for monitoring multiple physiological parameters (MMPP) continuously and simultaneously
US5552708A (en) * 1993-11-30 1996-09-03 U.S. Philips Corporation Magnetic resonance imaging apparatus comprising a communication system
US5964705A (en) * 1997-08-22 1999-10-12 Image-Guided Drug Delivery System, Inc. MR-compatible medical devices
US6052614A (en) * 1997-09-12 2000-04-18 Magnetic Resonance Equipment Corp. Electrocardiograph sensor and sensor control system for use with magnetic resonance imaging machines

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ES2244273A1 (en) * 2003-02-14 2005-12-01 Universidad Complutense De Madrid Multi modal compatible versatile respirator for use on subjects e.g. small experimentation animals, has control module to operate electromagnetic valves in pneumatic module as well as regulate lung pressure and flow of gases into lungs
WO2005116676A1 (en) * 2004-05-25 2005-12-08 Hvidovre Hospital Encoding and transmission of signals as rf signals for detection using an mr apparatus
EP1773191A2 (en) * 2004-07-23 2007-04-18 Medrad, Inc. Wireless patient monitoring device for magnetic resonance imaging
EP1773191A4 (en) * 2004-07-23 2009-11-11 Medrad Inc Wireless patient monitoring device for magnetic resonance imaging
WO2006099010A1 (en) * 2005-03-09 2006-09-21 Invivo Corporation Patient supported in-bore monitor for mri
WO2006099011A1 (en) * 2005-03-09 2006-09-21 Invivo Corporation Wireless in-bore patient monitor for mri
WO2006099009A1 (en) * 2005-03-09 2006-09-21 Invivo Corporation Wireless in-bore patient monitor for mri with integral display
US8121667B2 (en) * 2006-05-12 2012-02-21 Koninklijke Philips Electronics N.V. Interfaced base unit and display system for an MRI magnet room
EP2020839A2 (en) * 2006-05-12 2009-02-11 Invivo Corporation Method of transferring software and patient data in an mri wireless patient monitor system
EP2069987A2 (en) * 2006-05-12 2009-06-17 Invivo Corporation Method of interfacing a detachable display system to a base unit for use in mri
WO2007134165A3 (en) * 2006-05-12 2008-12-31 Invivo Corp Method of transferring software and patient data in an mri wireless patient monitor system
EP2069987A4 (en) * 2006-05-12 2010-06-09 Invivo Corp Method of interfacing a detachable display system to a base unit for use in mri
EP2020839A4 (en) * 2006-05-12 2010-09-29 Invivo Corp Method of transferring software and patient data in an mri wireless patient monitor system
DE102007045748A1 (en) * 2007-09-25 2009-04-09 Siemens Ag Adapter device for physiological signals and magnetic resonance apparatus with it
US9504429B1 (en) * 2012-06-28 2016-11-29 Fonar Corporation Apparatus for controlling the operation of an MRI system
US9660336B2 (en) 2013-02-07 2017-05-23 Kevan ANDERSON Systems, devices and methods for transmitting electrical signals through a faraday cage

Also Published As

Publication number Publication date
AU4049600A (en) 2000-11-10

Similar Documents

Publication Publication Date Title
JP5279993B2 (en) Data transmission to position sensor
JP4699694B2 (en) Wireless electrocardiogram system
US6019725A (en) Three-dimensional tracking and imaging system
US4763075A (en) Electro-optical isolator for magnetic resonance tomography
US4694837A (en) Cardiac and respiratory gated magnetic resonance imaging
US6652461B1 (en) Ultrasound device for three-dimensional imaging of internal structure of a body part
US5042486A (en) Catheter locatable with non-ionizing field and method for locating same
EP1659936B1 (en) Apparatus and method for cordless recording and telecommunication transmission of three special ecg leads and their processing
US4781200A (en) Ambulatory non-invasive automatic fetal monitoring system
US6233476B1 (en) Medical positioning system
ES2295158T3 (en) Wireless system of programmable electrodes for medical monitoring.
US5871446A (en) Ultrasonic medical system and associated method
ES2329773T3 (en) Electrodinamic sensors and applications of the same.
Ives et al. Monitoring the patient's EEG during echo planar MRI
Fischer et al. Novel real‐time R‐wave detection algorithm based on the vectorcardiogram for accurate gated magnetic resonance acquisitions
EP0879426B1 (en) Three-dimensional digital ultrasound tracking system
US7750635B2 (en) RF receive coil assembly with individual digitizers and means for synchronization thereof
US5782241A (en) Sensor device for electrocardiogram
US6306090B1 (en) Ultrasonic medical system and associated method
JP2006502809A (en) Apparatus and method for detecting abnormalities and inconsistencies in the body
KR101902594B1 (en) Wireless fetal monitoring system
US6505063B2 (en) Diagnostic imaging system with ultrasound probe
US20040242992A1 (en) Treatment system
US20050143667A1 (en) Wireless heart rate sensing system and method
JP3884489B2 (en) Plethysmograph for magnetic resonance imaging equipment.

Legal Events

Date Code Title Description
AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): GH GM KE LS MW SD SL SZ TZ UG ZW AM AZ BY KG KZ MD RU TJ TM AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE BF BJ CF CG CI CM GA GN GW ML MR NE SN TD TG

AK Designated states

Kind code of ref document: A1

Designated state(s): AE AL AM AT AU AZ BA BB BG BR BY CA CH CN CR CU CZ DE DK DM EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX NO NZ PL PT RO RU SD SE SG SI SK SL TJ TM TR TT TZ UA UG UZ VN YU ZA ZW

121 Ep: the epo has been informed by wipo that ep was designated in this application
DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
REG Reference to national code

Ref country code: DE

Ref legal event code: 8642

122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase in:

Ref country code: JP