Catheter navigation within an MR imaging device

• US 6,834,201 B2
• Filed: 05/05/2003
• Issued: 12/21/2004
• Est. Priority Date: 01/29/2001
• Status: Expired due to Term

• Current Assignee: University of Virginia Patent Foundation (University of Virginia)
• Original Assignee: Stereotaxis, Inc.
• Inventors: Hastings, Roger N., Gillies, George T., Broaddus, William C., Garibaldi, Jeffrey M.
• Primary Examiner(s): ROBINSON, DANIEL LEON
• Application Number:
  US10/429,524
• Publication Number:
  US 20030195412A1
• Time in Patent Office: 596 Days
• Field of Search: 600/411, 600/410, 600/407, 600/436, 324/307, 324/308, 324/309, 324/310, 324/207, 324/207.11, 324/207.23, 324/207.24, 324/207.25, 324/207.26, 436/173
• US Class Current: 600/411
• CPC Class Codes: A61B 2034/732 arranged around the patient, e.g. in a gantry
• CPC Class Codes: A61B 34/73 Manipulators for magnetic surgery
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: A61B 5/06 Devices, other than using radiation, for detecting or locating foreign bodies for removing same A61B17/50 ; determining position of probes within or on the body of the patient
• CPC Class Codes: A61M 25/01 Introducing, guiding, advancing, emplacing or holding catheters A61M25/10 takes precedence
• CPC Class Codes: G01R 33/285 Invasive instruments, e.g. catheters or biopsy needles, specially adapted for tracking, guiding or visualization by NMR

Abstract

A method of magnetically manipulating a medical device within a body part of a human patient in conjunction with MR imaging includes applying a navigating magnetic field with magnets from the MR imaging device, and changing the magnetic moment of the medical device to change the orientation of the medical device within the body part.

Claims

1. A method of navigating a medical device having a variable magnetic moment within an operating region within a patient, using an MR imaging device, the method comprising:

applying a static magnetic field to the operating region with an external magnet of an MR imaging device;

energizing at least one electromagnetic coil overlapping another electromagnetic coil of the medical device to create temporary magnetic moments in the medical device to change the orientation of the medical device with respect to the static magnetic field, and orient the medical device in a selected direction within the operating region.

2. The method according to claim 1 further comprising the step of moving a patient to vary the direction of the static magnetic field applied to the operating region by the external magnet of an MR imaging device to change the orientation of the medical device.

3. The method according to claim 1 wherein energizing at least one electromagnetic coil comprises reducing an effect of magnetic field coupling on the energizing using a twisted pair.

4. The method according to claim 1 wherein the MR imaging device is used to image the operating region in the patient'"'"'s body between navigations.

5. The method according to claim 1 in which the medical device comprises at least one set of three current carrying coils, and the step of creating temporary magnetic moments in the medical device comprises apply current to one or more of the current carrying coils.

6. The method according to claim 5 wherein there are at least two sets of three current carrying coils.

7. The method according to claim 1 in which the medical device comprises at least one set of three current carrying coils, and wherein the coils are used to receive signals during MR imaging to determine at least one of the location and orientation of the medical device.

8. The method according to claim 1 in which the medical device comprises at least one set of three current carrying coils, and wherein the coils are used to transmit and/or receive signals during MR imaging to enhance imaging adjacent the medical device.

9. The method according to claim 5 wherein the coils are mutually orthogonal.

10. The method according to claim 5 further comprising actively removing heat from the medical device generated by the current carrying coils.

11. The method according to claim 10 wherein heat is removed by circulating a cooling medium with the medical device.

12. The method according claim 10 wherein heat is removed using thermoelectric devices.

13. The method according to claim 10 wherein heat is removed using a heat pipe.

14. A method of navigating a medical device within an operating region in the body of a patient, the medical device having at least one coil therein, the method comprising:

establishing a navigating magnetic field in the operating region with an MR imaging device outside of the patient'"'"'s body;

selectively energizing the at least one coil in the medical device to create a magnetic moment in the medical device and creating a torque tending to align the magnetic moment of the magnetic medical device with the applied magnetic field; and

actively removing heat from the at least one coil through the medical device.

15. The method according to claim 14 further comprising varying the direction and/or intensity of the applied magnetic field applied by the MR imaging device to orient the medical device.

16. The method according to claim 14 wherein the step of selectively energizing the at least one coil comprises applying electrical energy in pulses to the at least one coil in the medical device.

17. The method according to claim 16 wherein the medical device is flexible and has a characteristic recovery time in which the device recovers from being flexed, and wherein the time between pulses in less than the characteristic recovery time of the medical device.

18. A method of navigating a medical device having a variable magnetic moment within an operating region within a patient, using an MR imaging device, the method comprising:

applying a static magnetic field to the operating region with an external magnet of an MR imaging device;

creating temporary magnetic moments in the medical device to change the orientation of the medical device with respect to the static magnetic field, and orient the medical device in a selected direction within the operating region;

wherein the medical device comprises at least two sets of three current carrying coils, and creating temporary magnetic moments in the medical device comprises applying current to one or more of the current carrying coils.

19. A method of navigating a medical device having a variable magnetic moment within an operating region within a patient, using an MR imaging device, the method comprising:

applying a static magnetic field to the operating region with an external magnet of an MR imaging device; and

applying electrical energy to create temporary magnetic moments in one or more coils in the medical device to change the orientation of the medical device with respect to the static magnetic field, and orient the medical device in a selected direction within the operating region; and

actively controlling heat resulting from applying the electrical energy in the medical device.

20. The method of claim 19, wherein actively controlling heat comprises applying the electrical energy in pulses to at least one coil.

21. The method of claim 19, wherein actively controlling heat comprises:

carrying a heat exchange medium into the medical device; and

cooling the heat exchange medium leaving the medical device.