JP4805456B2 - Electrode and electrode arrangement method suitable for functional magnetic resonance imaging apparatus - Google Patents

Description

[0001]
[Cross-reference of related applications]
This application is hereby incorporated by reference in its entirety, and is hereby incorporated by reference into this provisional US patent application 60/107, filed November 10, 1998 by Don DuRousseau. 918 claims priority.
[0002]
FIELD OF THE INVENTION
The present invention relates to medical devices, and in particular, is impure from the brain and body without using preamplified electronics while placed in the harsh operating environment generated by a functional magnetic resonance imaging (fMRI) device. Not related to the technology to acquire electrical signals.
[0003]
[Background of related applications]
Conventional EEG, EOG, ECG, EMG, and other physiological signals are usually recorded using individually placed electrodes attached to the skull and body using an adhesive or cap-type device. Examples of these techniques include Sams et al. (US Pat. No. 4,085,739) or Gevins et al. (US Pat. No. 4,967,038 and US Pat. No. 5,038,782). Has been developed by. In these attachment methods, electrodes are attached to amplifiers that are used to acquire and record the associated electrical and physiological activity. These amplifier devices require a very low contact impedance with the skin and are very sensitive to emissions from other electrical devices such as MRI devices. In such an environment, the input stage of a conventional EEG, ECG, or EMG amplifier is affected by the extremely large electric and magnetic fields generated by the magnetic resonance imaging device to the extent that the amplifier can no longer operate properly. Easy to receive. In addition, these amplifier devices are almost always operated from an AC voltage source and therefore emit electromagnetic interference (EMI), which impairs anatomical and functional data acquired by the fMRI device. And compromise the integrity of these data.
[0004]
Previous attempts by Ives et al. (US Pat. No. 5,445,162) to collect EEG signals in an fMRI environment have been made by attaching individual electrodes to the skull and electrically in the bore of the imaging device. It utilizes a battery-operated analog preamplifier device in which dynamic activity is amplified. These signals are then converted to light energy by additional analog circuitry located near the patient. Depending on the harsh fMRI environment, these signals are placed outside the shielded room along with fiber optic cables outside the shielded room that protect the imaging device from unwanted interference and also collect data. And transmitted to a secondary amplifying device attached to the PC for processing. However, this optically coupled preamplifier device is expensive and large and difficult to operate. In addition, the AC coupling of this device is due to dimensional constraints inside the head coil (located in the imaging device) and due to the design that the digital circuit cannot be used due to broadcast interference from the internal clock circuit. The nature of the mold is susceptible to large artifacts due to the transitional signals generated during normal operation of the imaging device.
[0005]
SUMMARY OF THE INVENTION
In accordance with the present invention, and to place the electrodes on the head and face acquiring an electrical signal, an elastic head cap for transmitting these electrical signals to an external amplifier device EEG electrodes used (hereinafter, quick referred to as a cap) By providing this positioning device, the above-mentioned problems of the prior art are solved. The quick cap provides an extensible elastic cap and chin strap portion that can easily accommodate a wide range of head size and shape differences. The quick cap provides a plurality of electrode holders designed to be filled with a conductive electrolyte. Further, the quick cap provides a wire harness assembly that can be configured with carbon or metal conductors and can be interconnected with any commercially available amplifier device.
[0006]
Some specific features and objects of the invention include the following.
The present invention quickly mounts a number of electrodes on the head and body that can acquire the signal within the fMRI apparatus and transmit it outside the shielded environment without any electronic amplification. Therefore, a low-cost apparatus is provided.
[0007]
Another object of the present invention is to limit the device's susceptibility to impure effects from the fMRI device, and to transmit signals outside the shielded fMRI environment to an amplifier attached to the PC for electrophysiological and The use of carbon wires attached to electrodes placed on the head and body to collect and process other physiologically correlated data.
[0008]
Another object of the present invention is to limit the device's sensitivity to physiological and electronically generated impure effects, each held within a flexible rubber electrode mount and connected to a carbon wire. Use a metal electrode made of tin, gold, silver-silver chloride, silver chloride powder combination or amalgam.
[0009]
Yet another object of the present invention is to further limit the susceptibility of the device to physiological and electronically generated impure effects to provide a carbon, carbonized plastic or conductive plastic connected to the carbon conductor. It is to use the electrode made.
[0010]
Yet another object of the present invention is to connect with carbon conductors to directly record signals from the brain or spinal cord while further limiting the device's susceptibility to physiological and electronically generated impure effects. Use a needle electrode, an implantable depth electrode or a cortical surface electrode.
[0011]
Yet another object of the present invention is to provide a mechanism for placing the electrode in the proper position on the skull, face, chest or body, thereby obtaining a single electrode or signal for acquiring signals from the eye, heart or muscle. It is to be able to use an electrode group.
[0012]
Yet another object of the present invention is to connect to signals from an external transducer device that is used to measure oxygen uptake, breathing, heart rate, impedance, movement, acceleration, force related signals or other signals. And allowing the use of a single conductor or group of conductors to transmit the signal.
[0013]
Yet another feature of the present invention is that the electrode holder and electrodes are placed on the head, face and body and are EEG, EOG, EMG, ECG and physiologically correlated from humans while in the magnetic resonance imaging device. To obtain other signals, it is necessary to provide separable elastic caps, chin straps and wire harness parts.
[0014]
The above and other features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
Objects, features and advantages of the present invention will become apparent from the following description.
[0015]
[Detailed Description of Preferred Embodiments]
As shown in FIG. 1, the fMRI compliant electrode placement apparatus of the present invention comprises an elastic fabric cap portion 10 and a chin strap portion 11, both of which are located in 13441 Liberty Lane, Gordonville, Virginia. Type NO. Manufactured by Liberty Fabrics. Preferably, it is made of a composite Lycra-Spandex® material such as 96175 black-09000. A plurality of electrode holders 20 a to 20 n are attached to the elastic cap portion 10. The sign “n” means that the number corresponds to the desired number of electrodes. For example, in typical applications, n can range from 1 to 1024. In FIG. 1, the plurality of conductive wires 13 of the present invention form a harness assembly 14. The conducting wire can be made of any non-ferrous magnetic conductive material, but is preferably made of carbon. The conductors are wound as a group with a mobile wrapping material (not shown) and extend away from the electrodes (not shown) held in electrode holders 20a-n away from the head, CHG series 40 manufactured by 3M Incorporated. End with a connector such as a pin connector (not shown). This flexible winding (not shown) is used to ensure that the wire cannot be coiled and prevents heating of the lead wire material while in the MRI machine environment Is done.
[0016]
As illustrated in FIGS. 2A-2D, the electrode holder 20 is preferably made of a single piece of molded medical grade EPDM rubber, such as Compound L-5099. The electrode holder 20 provides a central hole portion 21 that allows access to the central well portion 22 and is pressed against the skull surface. The central well portion 22 is filled so that a bridging portion can be formed that transmits an electric signal from the outer skin surface to an electrode (not shown) mounted on a ridge portion 23 disposed in the central well portion 22 of the electrode holder 20. The electrolytic solution is injected through the central hole 21. On the side of the electrode holder 20 near the top, there is a hole 24 where the conductive wire mounting portion of the electrode (not shown) extends from the electrode holder. In the outer portion of the electrode holder 20, there is a drawing portion 25. When the electrode holder is pushed through the elastic cap fabric 10, the elastic portion of the cap 10 is used by using two O-rings 25 in the drawing portion. Hold the fabric from above and below.
[0017]
As shown in FIGS. 3A to 3C, the electrode 30 of the present invention has a disc portion 31 having a central hole 32. The electrode 30 also includes a conductor attachment portion 33. The conductor attachment portion 33 extends outward from the disc portion 31 and provides a passage 34. Such a passage 34 may be created by drilling or other mechanisms. The drilling passage 34 provides an opening through which the conductor 13 passes, and the conductor is attached to the electrode 30 by caulking the attachment 33 onto the conductor 13.
[0018]
In a typical assembly sequence, an O-ring is fitted over the conductor 13. The electrode 30 is inserted into the central longitudinal hole portion 22 of the electrode holder 20 and rests on the raised portion 23 to ensure the correct position. The electrode holder is inserted through a button hole or other opening in the elastic fabric cap and secured by positioning one or more O-rings on the fabric. The conducting wire 13 is placed in the passage 34, and the mounting portion 33 is caulked onto the conducting wire.
[0019]
Another embodiment of a preferred electrode of the present invention is shown in FIGS. 4A-4F, in which a typical saddle-shaped electrode 40 is metal (eg, Specialized Labratory Equipment, 232 Selsdon Rd. South Croydon Surrey, UK, PN: metal manufactured by BO196 / 02) or conductive plastic 41 (for example, manufactured by Plastics One, 6591 Merriman Rd., SW, Roanoke, VA, PN: 36562). In a typical metal electrode, the central hole 43 is present to allow injection of electrolyte into the skin surface. In addition, a vertical hole portion 44 is provided to hold the electrolyte in contact with the electrode surface. In a typical conductive plastic electrode 41, a central hole 45 is present to allow electrolyte injection into the skin surface. A vertical hole 46 is again provided to hold the electrolyte in contact with the electrode surface. Both types of electrodes 40 and 41 can be easily carried in the electrode holder 20 of the present invention.
[0020]
Another embodiment of the preferred electrode of the present invention is shown in FIGS. 5A-5D, in which a conductive plastic electrode 50 (eg, Select Engineering Inc., 260 Lunenburg St., Fitchburg, MA, PN: SRT-3001). /LP/0.06) and carbon electrode 51 (eg, manufactured by Select Engineering Inc., 260 Lunenburg St., Fitchburg, MA, PN: SRT-3001 / CF / 40). In both cases, the non-metallic nature of the electrode material is such that the electrode is not affected by the induced currents present in the MRI (Magnetic Resonance Imaging) environment, as well as other physiological artifacts caused by the movement of the human body within the MRI apparatus. To. Conductive wire mounting means 52 is on the conductive plastic electrode 50. The conductor attachment means 52 provides a surface on which a conductive epoxy (eg, EPO-TEK E2101) is used to attach the carbon conductor 13 to the conductive plastic electrode 50. There is a vertical hole portion 53 on the carbon electrode 51. The vertical hole portion 53 holds the electrolyte in contact with the electrode surface. Conductor 13 is attached to carbon electrode 51 by use of a conductive epoxy at electrode attachment point 54. Both the conductive plastic electrode 50 and the carbon electrode 51 are carried in the electrode holder 20 of the present invention.
[0021]
Another embodiment of the preferred electrode of the present invention is shown in FIG. In FIG. 6, an implantable depth electrode assembly 60 (eg manufactured by AD-Technical Instrument Corp., 1901 William St., Racine, WI, PN: SP-10P) is used. The implantable depth electrode assembly 60 of this example includes 10 separate electrodes 61a-j. Each of the electrodes 61a-j obtains a signal from a different region of the brain. The depth electrode assembly 60 can be placed in the patient's cortex to collect electrical signals simultaneously from multiple depth regions of the brain. Although the depth electrode assembly 60 is not carried in the electrode holder 20 of the present invention, the lead wire assembly 14 is directly connected to the depth electrode assembly connection mechanism 62.
[0022]
Another embodiment of the preferred electrode of the present invention is shown in FIG. There, an assembly of subdural cortical surface electrodes, ie, assembly 70 (such as those manufactured by AD-Tech medical device company of 1901 William St., Racine, WI, PN: T-WS-20) is used. . In the example given, the subdural cortical surface electrode assembly 70 of this example has 20 separate electrodes 71a-t arranged in a grid pattern. Each grid pattern captures signals from different areas of the brain. However, there are other subdural cortical surface electrode assemblies that provide different numbers of electrodes. Grids with up to 128 separate electrodes (not shown) are readily available on the market, but other numbers of electrodes can be used. The subdural cortical surface electrode assembly 70 is placed on the patient's fur so as to collect signals from multiple regions of the brain lying under the grid pattern formed by the electrodes of the assembly. The subdural cortical surface electrode assembly 70 is not supported by the electrode holder 13 of the present invention, but rather the lead wire harness assembly 14 is directly connected to the subdural cortical surface electrode assembly connecting device 72.
[0023]
Another embodiment of the preferred electrode of the present invention is shown in FIG. There, subdural cortical surface electrode assemblies 80 (such as those manufactured by AD-Tech medical device companies of 1901 William St., Racine, WI, PN: T-WS-8) are used. The subdural cortical surface electrode assembly 80 of this example has eight separate electrodes 81a-h arranged in a strip pattern. Each strip pattern captures signals from different areas of the brain. However, other subdural cortical surface electrode assemblies that provide from 1 to 128 separate electrodes (not shown) are readily available on the market. The subdural cortical surface electrode assembly 80 is placed on the patient's fur so as to collect signals from multiple regions of the brain lying under the strip pattern formed by the electrodes of the assembly. The subdural cortical surface electrode assembly 80 is not supported by the electrode holder 13 of the present invention, but is connected directly to the lead wire harness assembly 14 via the assembly connection device 82.
[0024]
In operation, an assembled quick cap (Quik-Cap) is placed on the patient's head, and in a suitable embodiment, each electrode holder is then filled with a conductive solution. Some abrasion of the skin may be required during wearing to reduce the impedance at the skin electrolyte interface to an acceptable level determined by the input characteristics of the amplifier device to which the quick cap (Quik-Cap) is attached. .
[0025]
As discussed above, problems associated with collecting patient data in an MRI environment can be solved.
In this description, only the preferred embodiments of the invention have been shown and described, but as mentioned above, the invention can be used in various other combinations and environments and the presently described book Changes or modifications are possible within the scope of the inventive concept.
[Brief description of the drawings]
FIG. 1 illustrates an exemplary embodiment of an elastic cap of the present invention showing an electrode holder and conductor wire harness assembly with individual conductors attached to electrodes (not shown) held within the electrode holder. It is a side view of a chin string part.
2A is a cross-sectional side view of the electrode holder of FIG.
2B is a plan view of the embodiment of FIG. 2A.
2C is a side view of the embodiment of FIG. 2A.
2D is a plan view of a rubber O-ring used to attach the electrode holder to the elastic cap portion of FIG.
3A is a cross-sectional side view taken along line AA of FIG. 3B of an exemplary electrode held in the electrode holder of FIG. 2A.
3B is a plan view of the embodiment of FIG. 3A.
3C is a side view of the embodiment of FIG. 3A.
4A is a perspective plan view of one alternative embodiment of a cup-shaped electrode held in the exemplary electrode holder of FIG. 2A. FIG.
4B is a perspective bottom view of one alternative embodiment of a cup-shaped electrode held in the example electrode holder of FIG. 2A.
4C is a plan view of the embodiment of the electrode of FIG. 4A.
4D is a side view of the embodiment of the electrode of FIG. 4A.
4E is a cross-sectional view of an alternative embodiment of an embodiment of a conductive plastic electrode held within the electrode holder of FIG. 2A.
4F is a plan view of the embodiment of the electrode of FIG. 4E.
5A is an alternative embodiment plan view of an embodiment of a conductive plastic electrode embodiment held within the electrode holder of FIG. 2A. FIG.
FIG. 5B is a cross-sectional view of the conductive plastic electrode embodiment of FIG. 5A taken along line BB.
FIG. 5C is a plan view of an alternative embodiment of the embodiment of the carbon electrode held in the electrode holder of FIG. 2A.
5D is a cross-sectional side view taken along line CC of the embodiment of the carbon electrode of FIG. 5C.
FIG. 6 is a plan view of an alternative embodiment of an embodiment of a cortical depth electrode used with the carbon lead wire harness of the present invention.
FIG. 7 is a plan view of an alternative embodiment of a cortical surface grid electrode embodiment for use with the carbon wire harness of the present invention.
FIG. 8 is a plan view of an alternative embodiment of an embodiment of a cortical strip electrode used with the carbon conductor wire harness of the present invention.

Claims (11)

During operation of the magnetic resonance imaging apparatus, physiological electrical signals are collected in an environment where the magnetic resonance imaging apparatus is shielded from the outside, and the physiological electrical signals are transmitted outside the shielded environment without being amplified. A device that performs
A plurality of electrodes made of a non-ferromagnetic material;
A plurality of electrodes wires connected to the electrodes are made from non-ferromagnetic material, the electrode guide wire the electrode wire is wound in the winding material flexible enough not coiled The electrode conductor;
Equipped with the device.   2. The apparatus of claim 1, wherein the electrode is selected from the group consisting of silver, tin, gold, carbon, platinum, iridium, silver-silver chloride, electrically conductive plastic, carbonized plastic or carbon fiber combination material. Equipment manufactured in   2. The device of claim 1, wherein the electrode is a hypodermic needle, a subdural cortex electrode, or a subdural depth electrode.   2. The apparatus of claim 1, wherein the electrode conductor is silver, tin, gold, carbon, platinum, iridium, tinsel, stainless steel, Ag / AgCl amalgam, or a combination of electrically conductive plastic, carbonized plastic or carbon fiber. An apparatus made of a material selected from the group consisting of:   The apparatus according to claim 1, wherein each of the plurality of electrodes is disposed in an electrode holder.   6. The apparatus of claim 5, wherein the electrode holder is in the form of having one or more O-rings.   6. A device according to claim 5, wherein the electrode holder is made of a flexible material. During operation of the magnetic resonance imaging apparatus, physiological electrical signals are collected in an environment where the magnetic resonance imaging apparatus is shielded from the outside, and the physiological electrical signals are transmitted outside the shielded environment without being amplified. A device that performs
A plurality of electrodes;
An electrode lead wire which is not more amplified coupled to the electrode, the electrode guide wire the electrode wire is wound in the winding material flexible enough not coiled, silver, tin, gold, carbon Said electrode wire made of a material selected from the group consisting of platinum, iridium, tinsel, stainless steel, Ag / AgCl amalgam, or a combination of electrically conductive plastic, carbonized plastic or carbon fiber;
An apparatus, so as not to interfere with the magnetic resonance image data. While the functional magnetic resonance imaging apparatus or the magnetic brain imaging apparatus is operating, the physiological electrical signals are collected in an environment in which the magnetic resonance imaging apparatus is shielded from the outside, and the physiological electrical signals are amplified. A device for transmitting outside the shielded environment without
A plurality of electrodes held in place by a flexible coating material;
A plurality of electrodes wires connected to the electrodes are made from non-ferromagnetic material, the electrode guide wire the electrode wire is wound in the winding material flexible enough not coiled The electrode conductor;
Equipped with the device. Electrical data of the functional magnetic resonance imaging apparatus is collected in an environment where the functional magnetic resonance imaging apparatus is shielded from the outside during operation of the functional magnetic resonance imaging apparatus without interfering with the magnetic resonance imaging data. A method of transmitting the electrical data outside the shielded environment without amplification ;
Placing a plurality of electrodes in skin contact with a human body placed in the shielded environment;
Connecting the electrode to one end of an electrode lead ;
Coupling a second end of the electrode conductor to an amplifying device disposed outside the shielded environment;
Winding a flexible wrapping material around the electrode conductor to such an extent that the electrode conductor is not coiled . Collecting electrophysiological data of the functional magnetic resonance imaging device in an environment shielded from the outside during operation of the functional magnetic resonance imaging device without interfering with the magnetic resonance imaging data And transmitting the electrophysiological data outside the shielded environment without amplification, comprising :
Providing a plurality of electrodes made of a non-ferromagnetic material;
Coupling the electrode to an electrode lead made from a non-ferromagnetic material;
And said electrode wire is wound a wound flexible material but this is not coiled on the electrode lead,
A method.

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