Device and method for preventing magnetic-resonance imaging induced damage

• US 20050113676A1
• Filed: 03/08/2004
• Published: 05/26/2005
• Est. Priority Date: 04/02/2003
• Status: Abandoned Application

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Biophan Technologies Incorporated
• Inventors: Connelly, Patrick R., Weiner, Michael L., Miller, Victor R., Helfer, Jeffrey L.
• Application Number:
  US10/795,743
• Publication Number:
  US 20050113676A1
• Time in Patent Office: Days
• US Class Current: 600/421
• CPC Class Codes: A61N 1/086 Magnetic resonance imaging [MRI] compatible leads
• CPC Class Codes: G01R 33/285 Invasive instruments, e.g. catheters or biopsy needles, specially adapted for tracking, guiding or visualization by NMR
• CPC Class Codes: G01R 33/288 Provisions within MR facilities for enhancing safety during MR, e.g. reduction of the specific absorption rate [SAR], detection of ferromagnetic objects in the scanner room
• CPC Class Codes: G01R 33/4804 Spatially selective measurement of temperature or pH
• CPC Class Codes: Y10T 428/24322 Composite web or sheet
• CPC Class Codes: Y10T 428/24331 including nonapertured component

Abstract

An electromagnetic shield has a first patterned or apertured layer having non-conductive materials and conductive material and a second patterned or apertured layer having non-conductive materials and conductive material. The conductive material may be a metal, a carbon composite, or a polymer composite. The non-conductive materials in the first patterned or apertured layer may be randomly located or located in a predetermined segmented pattern such that the non-conductive materials in the first patterned or apertured layer are located in a predetermined segmented pattern with respect to locations of the non-conductive materials in the second patterned or apertured layer.

Claims

1. A device for amplifying an electrical signal of physiological significance in a magnetic-resonance imaging environment, comprising:

at least two electrodes with associated input leads for coupling to a patient;

an amplifier having a zero-signal reference terminal for detecting and amplifying the desired physiological signal; and

a filter, connected to said input leads and coupling said at least two electrodes to said amplifier, to attenuate any induced RF signal produced in the magnetic-resonance imaging environment and passing the lower frequency desired electrical physiological signal;

said filter including a shield enclosing said filter;

said shield enclosing said filter being patterned with non-conductive materials and conductive materials.

2. The device as claimed in claim 1, wherein said filter further includes a low pass filter connected to one of said input leads.

3. The device as claimed in claim 1, wherein said conductive material is a metal.

4. The device as claimed in claim 1, wherein said conductive material includes metal-coated carbon filaments.

5. The device as claimed in claim 1, wherein said conductive material is a polymer composite.

6. The device as claimed in claim 1, wherein said shield is constructed of two patterned sheaths, each patterned sheath having non-conductive materials and conductive materials.

7. The device as claimed in claim 6, wherein said conductive materials in one of said two patterned sheaths are randomly located.

8. The device as claimed in claim 6, wherein said conductive materials in said two patterned sheaths are located in a predetermined segmented pattern.

9. The device as claimed in claim 1, further comprising:

an input lead shield to shield said input leads.

10. The device as claimed in claim 9, wherein said input lead shield is patterned with non-conductive materials and conductive materials.

11. The device as claimed in claim 10, wherein said conductive material of said input lead shield is a metal.

12. The device as claimed in claim 10, wherein said conductive material of said input lead shield includes metal-coated carbon filaments.

13. The device as claimed in claim 10, wherein said conductive material of said input lead shield is a polymer composite.

14. The device as claimed in claim 10, wherein said input lead shield is constructed of two patterned sheaths, each patterned sheath having non-conductive materials and conductive materials.

15. The device as claimed in claim 14, wherein said conductive materials in one of said two patterned sheaths are randomly located.

16. The device as claimed in claim 14, wherein said conductive materials in said two patterned sheaths are located in a predetermined segmented pattern.

17. The device as claimed in claim 14, wherein said conductive materials in said two patterned sheaths are located in a predetermined segmented pattern with respect to a direction substantially parallel with an axis of said input leads.

18. The device as claimed in claim 14, wherein said conductive materials in said two patterned sheaths are located in a predetermined segmented pattern with respect to a direction substantially perpendicular with an axis of said input leads.

19. The device as claimed in claim 17, wherein said conductive materials in said two patterned sheaths are located in a predetermined segmented pattern with respect to a direction substantially perpendicular with an axis of said input leads.

20. A device for amplifying an electrical signal of physiological significance in a magnetic-resonance imaging environment, comprising:

at least two electrodes with associated input leads for coupling to a patient;

an amplifier having a zero-signal reference terminal for detecting and amplifying the desired physiological signal; and

a filter, connected to said input leads and coupling said at least two electrodes to said amplifier, to attenuate any induced RF signal produced in the magnetic-resonance imaging environment and passing the lower frequency desired electrical physiological signal,

said filter including a shield enclosing said filter;

said shield being an apertured conductive material having a maximum aperture dimension of 0.01 millimeters to 10 millimeters.

21. The device as claimed in claim 20, wherein said filter further includes a low pass filter connected to one of said input leads.

22. The device as claimed in claim 20, wherein said conductive material is a metal.

23. The device as claimed in claim 20, wherein said conductive material includes metal-coated carbon filaments.

24. The device as claimed in claim 20, wherein said conductive material is a polymer composite.

25. The device as claimed in claim 20, wherein said conductive material comprises nanotubes.