Apparatuses and methods for electrophysiological signal delivery and recording during MRI

• US 10,327,701 B2
• Filed: 11/21/2005
• Issued: 06/25/2019
• Est. Priority Date: 05/06/2005
• Status: Active Grant

• Current Assignee: The General Hospital Corporation (Mass General Brigham, Inc.)
• Original Assignee: The General Hospital Corporation (Mass General Brigham, Inc.)
• Inventors: Bonmassar, Giorgio, Purdon, Patrick L.
• Primary Examiner(s): Berhanu, Etsub D
• Application Number:
  US11/913,641
• Publication Number:
  US 20080306397A1
• Time in Patent Office: 4,964 Days
• Field of Search: 600372-373, 600386, 600388, 600393, 600395-396, 600410-411, 600527, 600382, 600544-545, 439909
• CPC Class Codes: A61B 5/1102 Ballistocardiography
• CPC Class Codes: A61B 5/291 for electroencephalography [EEG]
• CPC Class Codes: A61B 5/6814 Head
• CPC Class Codes: A61B 5/721 using a separate sensor to detect motion or using motion information derived from signals other than the physiological signal to be measured

Abstract

Methods, systems and arrangements are provided for obtaining electroencephalograph (“EEG”) EEG signals from a patient e.g., during a concurrent EEG/MRI examination of the patient. The methods, systems and arrangements include a cap made of conductive inks with sensor positions for attaching a plurality of sensors to the patient'"'"'s head. The sensors can include electrodes as well as motion sensors for improving EEG signal quality and MRI image quality in the presence of motion noise and other artifacts within the MRI environment. The electrodes may be composed of conductive inks, and can be used in high magnetic fields due to a weak interaction with the RF fields generated by the MRI scanner. The exemplary methods, systems and arrangements can achieve lower SAR and lower temperature increase, as compared to conventional electrodes.

Claims

1. A system for transmitting electrical signals to or from the head of a subject, the system comprising:

an electrode carrier;

a plurality of electrodes configured to transmit electrical signals and connected to the carrier, the carrier configured and arranged for placement on the head of the subject and, upon placement thereon, arranged to position the electrodes for transmitting electrical signals to or from the head;

a conductive trace configured to be electrically connected to the subject to receive or deliver the electrical signals; and

wherein each electrode includes a conductive lead electrically extending from the conductive trace to communicate the electrical signals, the conductive lead configured to be electrically isolated from the subject and extending to a connector, and the conductive lead constructed of a predetermined amount of a conductive ink forming a conductive ink layer, the predetermined amount of the conductive ink being substantially dispersed through the extent of the conductive lead, the predetermined amount of the conductive ink having a resistivity in a range of 1 kilo-ohm·

meter to 100 kilo-ohm·

meters, the resistivity of the predetermined amount of the conductive ink selected to reduce exposure from RF pulses used during magnetic resonance imaging.

2. The system of claim 1 further comprising a motion sensor configured to at least detect ballistocardiogram motion.

3. The system of claim 2 wherein the motion sensor includes a piezo-electric sensor.

4. The system of claim 2 wherein the motion sensor is connected to the electrode carrier.

5. The system of claim 1 wherein the conductive trace has a resistivity of at least 25 kilo-ohm·

meters.

6. The system of claim 5 wherein the conductive trace and the conductive lead include at least one of carbon, silver, and silver chloride.

7. The system of claim 1 wherein the conductive trace and the conductive lead include a polymer thick film.

8. The system of claim 1 wherein the conductive trace forms a partial circle and the conductive lead is electrically connected to the conductive trace between two endpoints of the partial circle so as to reduce eddy currents induced by an applied RF signal.

9. The system of claim 1 wherein the conductive lead includes a plurality of layers including at least one of a foam layer, a polyester layer, a conductive ink layer, a dielectric layer, and a silicone layer.

10. The system of claim 1 wherein the carrier forms a stretchable cap.

11. The system of claim 10 wherein the stretchable cap includes a polyester substrate and having connected thereto a plurality of microstrips of conductive ink forming the conductive leads.

12. The system of claim 11 wherein the conductive ink is coated with dielectric ink.

13. The system of claim 12 wherein the carrier includes a vibration dampener including at least one of an elastic mesh dressing and a pillow.

14. The system of claim 11 wherein the conductive trace is connected to the polyester substrate.

15. The system of claim 1 wherein the conductive trace and the conductive lead are free of ferromagnetic materials.

16. The system of claim 1 configured and arranged for receiving electroencephalogram (EEG) signals.

17. The system of claim 1 configured and arranged for delivering stimulation to the subject.

18. The system of claim 1 wherein the conductive lead has a length between about 35 cm and 56 cm.

19. A system for delivering or receiving electrical signals to or from the head of a subject, the system comprising:

an electrode carrier;

a plurality of electrodes configured to communicate electrical signals and connected to the carrier, the carrier configured and arranged for placement on the head of the subject and, upon placement thereon, arranged to position the electrodes for transmitting electrical signals to or from the head;

a conductive trace configured to be electrically connected to the subject to communicate the electrical signals;

wherein each electrode includes a conductive lead electrically extending from the conductive trace to communicate the electrical signals, the conductive lead configured to be electrically isolated from the subject and extending to a connector;

wherein the conductive lead comprises a polymer thick film, the polymer thick film having a resistivity in a range of 1 kilo-ohm·

meter to 100 kilo-ohm·

meters, the resistivity of the polymer thick film selected to reduce exposure from RF pulses used during magnetic resonance imaging, said resistivity substantially dispersed through the extent of the conductive lead; and

wherein the conductive trace forms a partial circle and the conductive lead is electrically connected to the conductive trace between two endpoints of the partial circle.

20. The system of claim 19 further comprising a motion sensor configured to at least detect ballistocardiogram motion.

21. The system of claim 20 wherein the motion sensor includes a piezo-electric sensor.

22. The system of claim 19 wherein the conductive trace has a resistivity of at least 25 kilo-ohm·

meters.

23. The system of claim 19 wherein the conductive lead has a length between about 35 cm and 56 cm.