Optical MRI catheter system

• US 20050203378A1
• Filed: 05/02/2005
• Published: 09/15/2005
• Est. Priority Date: 07/25/2002
• Status: Active Grant

• Current Assignee: Biophan Technologies Incorporated
• Original Assignee: Biophan Technologies Incorporated
• Inventors: Gray, Robert W., MacDonald, Stuart G., Thomas, Christopher, Helfer, Jeffrey L.
• Granted Patent: US 6,980,848 B2
• Time in Patent Office: Days
• US Class Current: 600/410
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• 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 33/34084 implantable coils or coils being geometrically adaptable to the sample, e.g. flexible coils or coils comprising mutually movable parts
• CPC Class Codes: G01R 33/3692 involving signal transmission without using electrically conductive connections, e.g. wireless communication or optical communication of the MR signal or an auxiliary signal other than the MR signal

Abstract

An assembly for delivering optical signals comprising a nuclear magnetic resonance system; an optical interface assembly electrically connected to the nuclear magnetic resonance system, the optical interface assembly comprising a first laser for producing laser optical signals, an interface optical to electrical signal convertor, and an interface optical connector assembly; and a catheter assembly comprising a proximal end, a distal end, and a catheter optical connector assembly disposed at the proximal end and connected to the interface optical connector assembly of the optical interface assembly, a fiber optic cable assembly, an electronics assembly disposed at the distal end comprised of a catheter electrical to optical signal convertor and a catheter optical to electrical signal convertor, and a first receiving coil disposed at the distal end.

Claims

1. An assembly for delivering optical signals comprising a nuclear magnetic resonance system;

an optical interface assembly electrically connected to said nuclear magnetic resonance system, said optical interface assembly comprising a first laser for producing laser optical signals, an interface optical to electrical signal convertor, and an interface optical connector assembly; and

a catheter assembly comprising a proximal end, a distal end, and a catheter optical connector assembly disposed at said proximal end and connected to said interface optical connector assembly of said optical interface assembly, a fiber optic cable assembly, an electronics assembly disposed at said distal end comprised of a catheter electrical to optical signal convertor and a catheter optical to electrical signal convertor, and a first receiving coil disposed at said distal end, wherein;

a. said laser optical signals received through said fiber optic cable assembly from said first laser are converted into catheter electrical signals by said catheter optical to electrical signal convertor;

b. said first receiving coil is adapted to receive electromagnetic signals and deliver coil electrical signals to said electronics assembly of said catheter assembly;

c. said coil electrical signals are converted by said catheter electrical to optical signal convertor to catheter optical signals and said catheter optical signals are delivered through said fiber optic cable assembly to said interface optical to electrical signal convertor; and

d. said catheter optical signals are converted by said interface optical to electrical signal convertor into interface electrical signals and are delivered to said nuclear magnetic resonance system.

2. The assembly as recited in claim 1, wherein said catheter optical to electrical signal convertor is comprised of a photovoltaic cell.

3. The assembly as recited in claim 1, wherein said interface optical to electrical signal convertor is comprised of a photodiode.

4. The assembly as recited in claim 1, wherein said electronics assembly of said catheter assembly further comprises a switch for blocking or permitting the passage of said coil electrical signals to said catheter electrical to optical signal convertor.

5. The assembly as recited in claim 4, wherein said switch is opened by the delivery of light from said first laser to said catheter optical to electrical signal convertor.

6. The assembly as recited in claim 4, wherein said assembly further comprises a second receiving coil, and wherein said switch is a multi-state switch used to select which of said first or second receiving coils provides said coil electrical signal to said electronics assembly of said catheter assembly.

7. The assembly as recited in claim 1, wherein said catheter electrical to optical signal convertor further comprises a reference signal source.

8. The assembly as recited in claim 1, wherein said electronics assembly of said catheter assembly further comprises a detuning assembly adapted to change the resonance frequency of said first receiving coil.

9. The assembly as recited in claim 8, wherein said electronics assembly of said catheter assembly further comprises a switch, and said detuning assembly further comprises at least one capacitor whose capacitance changes with the application of a potential difference to said switch.

10. The assembly as recited in claim 8, wherein said receiving coil further comprises a single inductive loop coil, and a tuning capacitor.

11. The assembly as recited in claim 8, wherein said electronics assembly of said catheter further comprises a command extraction component for filtering a detuning command to said detuning assembly.

12. The assembly as recited in claim 1, wherein said first receiving coil is selected from the group consisting of a pickup coil, a single loop coil, a multi-loop coil, a loopless antenna, and a dipole antenna.

13. The assembly as recited in claim 1, wherein said first laser is modulated to produce said laser optical signals to said catheter optical to electrical signal convertor.

14. The assembly as recited in claim 13, wherein said first laser provides electrical power to said electronics assembly of said catheter and control signals to said electronics assembly of said catheter.

15. The assembly as recited in claim 1, wherein said optical interface assembly further comprises a second laser, and wherein said first laser generates optical command/gating signals to said electronics assembly of said catheter and said second laser generates optical power for use by said electronics assembly of said catheter.

16. The assembly as recited in claim 1, wherein:

a. said first laser produces laser optical signals at a first wavelength;

b. said catheter electrical to optical signal convertor converts said coil electrical signals to said catheter optical signals, said catheter optical signals being at a second wavelength;

c. said electronics assembly of said catheter assembly further comprises a catheter optical filter/mirror component that delivers said laser optical signals at said first wavelength from said optical interface assembly to said catheter optical to electrical signal convertor, and that delivers said catheter optical signals at said second wavelength from said catheter electrical to optical signal convertor to said optical interface assembly; and

d. said optical interface assembly further comprises an interface optical filter/mirror component that delivers said laser optical signals at said first wavelength from said first laser to said electronics assembly of said catheter assembly, and that delivers said catheter optical signals at said second wavelength from said catheter electrical to optical signal convertor to said interface optical to electrical signal convertor.

17. The assembly as recited in claim 16, wherein said catheter optical filter/mirror component reflects said catheter optical signals at said second wavelength to said optical interface assembly, and transmits said laser optical signals at said first wavelength to said catheter optical to electrical signal convertor.

18. The assembly as recited in claim 16, wherein said interface optical filter/mirror component reflects said laser optical signals of said first wavelength to said electronics assembly of said catheter assembly, and transmits said catheter optical signals at said second wavelength to said interface optical to electrical signal convertor.

19. The assembly as recited in claim 18, wherein said catheter optical filter/mirror component reflects said catheter optical signals at said second wavelength to said optical interface assembly, and transmits said laser optical signals at said first wavelength to said catheter optical to electrical signal convertor.

20. The assembly as recited in claim 19, wherein said first wavelength is between about 450 and about 650 nanometers, and said second wavelength is between about 750 and about 1000 nanometers.

21. The assembly as recited in claim 19, wherein said a fiber optic cable assembly of said catheter assembly is comprises of a single strand of optical fiber for transmission of said laser optical signals at said first wavelength and said catheter optical signals at said second wavelength.

22. The assembly as recited in claim 16, wherein said interface optical filter/mirror component and said catheter optical filter/mirror component are selected from the group consisting of a dichroic color filter, a hot mirror, and a cold mirror.