Magnetic resonance imaging interference immune device

• US 20060041294A1
• Filed: 08/19/2005
• Published: 02/23/2006
• Est. Priority Date: 08/20/2004
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Biophan Technologies Incorporated
• Inventors: Gray, Robert W.
• Granted Patent: US 8,041,433 B2
• Time in Patent Office: Days
• US Class Current: 607/116
• CPC Class Codes: A61N 1/05 for implantation or insertion into the body, e.g. heart electrode A61N1/06 takes precedence
• CPC Class Codes: H01B 7/048 for implantation into a human or animal body, e.g. pacemaker leads
• CPC Class Codes: H01B 7/065 having the shape of an helix

Abstract

A wire form includes a conductor having a distal end and a proximal end. The conductor is coiled and has a predetermined spacing between adjacent coils. The predetermined spacing provides a parasitic capacitance and an inductance. The parasitic capacitance and inductance have a resonance frequency tuned to about an excitation signal'"'"'s frequency of a magnetic-resonance imaging scanner.

Claims

1. A wire form, comprising:

a conductor having a distal end and a proximal end;

said conductor being coiled;

said conductor having a predetermined spacing between adjacent coils, said predetermined spacing providing a parasitic capacitance and an inductance, said parasitic capacitance and inductance having a resonance frequency shifted towards an excitation signal'"'"'s frequency of a magnetic-resonance imaging scanner.

2. The wire form as claimed in claim 1, wherein said conductor is a coaxial cable.

3. The wire form as claimed in claim 1, wherein said conductor is a spring wire form coated with an electrically insulative layer, an electrically conductive shielding layer, and a protective and electrically insulative layer.

4. The wire form as claimed in claim 1, wherein said conductor is a conductor in a bipolar pacing lead circuit.

5. The wire form as claimed in claim 1, wherein said conductor is a conductor in a unipolar pacing lead circuit.

6. The wire form as claimed in claim 1, wherein said conductor is a conductor in a cardiac defibrillator lead.

7. The wire form as claimed in claim 1, wherein said conductor is a conductor in a deep brain stimulating lead.

8. The wire form as claimed in claim 1, wherein said conductor is a conductor in a nerve stimulating lead.

9. The wire form as claimed in claim 1, wherein said parasitic capacitance and inductance have a resonance frequency approximately equal to an excitation signal'"'"'s frequency of a magnetic-resonance imaging scanner.

10. The wire form as claimed in claim 1, wherein said parasitic capacitance and inductance have a resonance frequency near an excitation signal'"'"'s frequency of a magnetic-resonance imaging scanner.

11. The wire form as claimed in claim 1, wherein said parasitic capacitance and inductance have a resonance frequency greater than an excitation signal'"'"'s frequency of a magnetic-resonance imaging scanner.

12. A method for forming a wire form, comprising:

(a) stretching a spring wire form to create gaps between adjacent coils, the gaps providing a parasitic capacitance and an inductance, the parasitic capacitance and inductance having a resonance frequency not tuned to an excitation signal'"'"'s frequency of a magnetic-resonance imaging scanner.

13. A method for forming a wire form, comprising:

(a) coating a conductor with an electrically insulative layer, an electrically conductive shielding layer, and a protective and electrically insulative layer;

(b) coiling the coated conductor such that the coiled coated conductor provides a parasitic capacitance and an inductance, the parasitic capacitance and inductance having a resonance frequency not tuned to an excitation signal'"'"'s frequency of a magnetic-resonance imaging scanner.