FMRI compatible electrode and electrode placement techniques

• US 6,708,051 B1
• Filed: 08/29/2001
• Issued: 03/16/2004
• Est. Priority Date: 11/10/1998
• Status: Expired due to Term

• Current Assignee: Compumedics Limited
• Original Assignee: Compumedics Limited
• Inventors: Durousseau, Donald R.
• Primary Examiner(s): LAYNO, CARL HERNANDZ
• Application Number:
  US09/831,687
• Time in Patent Office: 930 Days
• Field of Search: 600/372, 600/382, 600/383, 600/393, 600/395, 600/410, 600/411, 600/421
• US Class Current: 600/383
• CPC Class Codes: A61B 2562/0215 Silver or silver chloride containing
• CPC Class Codes: A61B 2562/0217 Electrolyte containing
• CPC Class Codes: A61B 5/291 for electroencephalography [EEG]

Abstract

An apparatus for monitoring an electrophysiological signal within a magnetically sensitive apparatus comprises a stretchable elastic cap having a plurality of electrode holders designed to be filled with a conductive electrolyte. Electrodes are disposed within the electrode holders and leads extend from the electrodes. The electrodes and the leads are made of a non-ferromagnetic conductive material.

Claims

1. An apparatus for collecting physiological electrical signals inside of a magnetic resonance imaging system (MRI) during normal operation of the MRI system, the apparatus comprising:

a plurality of electrodes wherein the electrodes are made of a non-ferromagnetic conductive material;

one or more electrode leads connected to said electrodes wherein the leads are made of a nonferromagnetic conductive material and wherein at least two electrode leads are enclosed by flexible material configured to prevent coiling.

2. The apparatus of claim 1, wherein the electrodes are manufactured from a material selected from the group consisting of:

Silver, Tin, Gold, Carbon, Platinum, Iridium, Silver/Silver Chloride, Conductive Plastic, Carbonized Plastic and Carbon Fibers.

3. The apparatus of claim 1, wherein the electrodes are subdermal needles, subdural cortical surface electrodes, or subdural depth electrodes.

4. The apparatus of claim 1, wherein the electrode leads are manufactured from a material selected from the group the group consisting of:

Silver, Tin, Gold, Carbon, Platinum, Iridium, Silver/Silver Chloride, Conductive Plastic, Carbonized Plastic and Carbon Fibers.

5. The apparatus of claim 1, wherein each of said one or more electrodes is positioned within an electrode holder.

6. The apparatus of claim 5, wherein the electrode holder is configured to accommodate one or more O-rings.

7. The apparatus of claim 5, wherein the electrode holder is made of a flexible material.

8. An apparatus for collecting physiological electrical signals inside of a shielded environment of a functional magnetic resonance imaging (MRI) system during normal operation of the MRI system and carrying such signals without amplification outside of the shielded environment, the apparatus comprising:

one or more electrodes,

one or more non-amplifying electrode lead connected to aid electrodes, wherein at least two electrode leads are enclosed by flexible material configured to prevent coiling, and wherein the electrode leads are manufactured from a material selected from the group consisting of;

Silver, Tin, Gold, Carbon, Platinum, Iridium, Silver/Silver Chloride, Conductive Plastic, Carbonized Plastic, and Carbon Fibers,

whereby the apparatus is configured to not interfere with the integrity of MRI data.

9. An apparatus for collecting physiological electrical signals inside of a shielded environment of a functional magnetic resonance imaging (MRI) system during normal operation of the MRI system and carrying such signals without amplification outside of the shielded environment, the apparatus comprising:

one or more electrodes, and

one or more non-amplifying electrode leads connected to said electrodes,

wherein the electrode leads conduct signals over a distance of more than 10 feet,

whereby the apparatus is configured to not interfere with the integrity of MRI data.

10. An apparatus for collecting physiological electrical signals inside of a shielded environment of a functional magnetic resonance imaging (MRI) system during, normal operation of the MRI system and carrying such signals without amplification outside of the shielded environment, the apparatus comprising:

one or more electrodes,

one or more electrode holders having an electrode positioned therein, and wherein the electrode holder contains an opening through which electrolyte can be applied to the patient; and

one or more non-amplifying electrode leads connected to said electrodes, wherein the leads conduct signals over a distance of more than 10 feet,

whereby the apparatus is confined to not interfere with the integrity of MRI data.

11. An apparatus for collecting physiological electrical signals inside of a shielded environment of a functional magnetic resonance imaging (MRI) system during normal operation of the MRI system and carrying such signals without amplification outside of the shielded environment, the apparatus comprising;

one or more electrodes,

one or more rubber electrode holders having an electrode positioned therein, and wherein the electrode holder contains an opening through which electrolyte can be applied to the patient, and

one or more non-amplifying electrode leads connected to said electrodes, wherein the leads conduct signals over a distance of more than 10 feet,

whereby the apparatus is configured to not interfere with the integrity of MRI data.

12. An apparatus for collecting physiological electrical signals inside of a shielded environment of a functional magnetic resonance imaging (MRI) system during normal operation of the MRI system and carrying such signals without amplification outside of the shielded environment, the apparatus comprising:

one or more electrodes,

an elastic cap for placement on a patient'"'"'s head;

a plurality of electrode holders mounted to the cap; and

one or more non-amplifying electrode leads connected to said electrodes, wherein the leads conduct signals over a distance of more than 10 feet,

whereby the apparatus is configured to not interfere with the integrity of MRI data.

13. An apparatus for collecting physiological electrical signals during normal operation of a Magnetoencephalography (MEG) system and carrying such signals without amplification outside of the shielded environment of the MEG system, the apparatus comprising:

a plurality of nonmetallic electrodes; and

one or more electrode leads connected to said electrodes wherein the leads are made of a non-ferromagnetic conductive material and wherein at least two electrode leads are enclosed by flexible material configured to prevent coiling.

14. An apparatus for collecting physiological electrical signals inside of a shielded environment of a functional magnetic resonance imaging (MRI) system during normal operation of the MRI system or an operating magnetoencephalography (MEG) system and carrying such signals without amplification outside of the shielded environment, the apparatus comprising:

one or more electrodes being held in place by a flexible wrapping material; and

one or more electrode leads connected to said electrodes wherein the leads are made of a non-ferromagnetic conductive material and wherein at least two electrode leads are enclosed by flexible material configured to prevent coiling.

15. A method of collecting electrical data inside of a shielded environment of a functional magnetic resonance imaging (MRI) system during normal operation of the MRI system without interfering with the integrity of the MRI data, the method comprising the steps of:

placing one or more electrodes in dermal contact with a patient located inside of the shielded environment;

connecting said electrodes to one end of a lead wire;

connecting a second end of said lead wire to an amplifier system located outside of said shielded environment.

16. The method of claim 15, wherein said electrodes are made from a non-ferromagnetic material.

17. The method of claim 15, wherein said lead wires are made from a non-ferromagnetic material.

18. The method of claim 16 or 17 wherein said non-ferromagnetic material is one of a the group consisting of:

Silver, Tin, Gold, Carbon, Platinum, Iridium, Silver/Silver Chloride, Conductive Plastic, Carbonized Plastic and Carbon Fibers.

19. The method of claim 15, further comprising the steps of:

mounting one or more electrode holder in a flexible cap; and

inserting said electrodes into said electrode holders.

20. The method of claim 19, further comprising, the step of wrapping said lead wires with a flexible material.

21. The method of claim 19, further comprising the step of securing said flexible cap to the head of said patient ting a strap.

22. The method of claim 21, further comprising the step of adjusting the length of the strap using at least one Velcro™

connection between the strap and the cap.

23. The method of claim 15, further comprising the step of mounting at least one of the electrodes to a patient using a flexible wrapping to prevent coiling.

24. An apparatus for collecting electrophysiological data in a magnetically sensitive environment, the apparatus comprising:

a signal amplification system;

an electrode made of a non-ferromagnetic material;

a lead made of a non-ferromagnetic material and extending from the electrode, the lead being conductively coupled to the signal amplification system and being of sufficient length to enable the signal amplification system to be placed beyond the magnetically sensitive environment.

25. A method of collecting electrophysiological data in a magnetically sensitive environment, the method comprising:

providing a plurality of electrodes wherein the electrodes are made of a non-ferromagnetic conductive material; and

connecting said electrodes to leads made of a non-ferromagnetic conductive material; and

enclosing the leads in a flexible material configured to prevent coiling.