MRI-guided catheters

• US 8,825,133 B2
• Filed: 01/24/2013
• Issued: 09/02/2014
• Est. Priority Date: 06/16/2009
• Status: Active Grant

• Current Assignee: Clearpoint Neuro, Inc.
• Original Assignee: MRI Interventions, Inc. (Clearpoint Neuro, Inc.)
• Inventors: Jenkins, Kimble L., Piferi, Peter, Vij, Kamal, Ghidoli, Daniele, Flores, Jesse, Karmarkar, Parag V., Pandey, Rajesh
• Primary Examiner(s): Cattungal, Sanjay
• Application Number:
  US13/749,351
• Publication Number:
  US 20130131496A1
• Time in Patent Office: 586 Days
• Field of Search: 600407-429, 600473-480, 607119-123, 324307-309, 324/318
• US Class Current: 600/423
• CPC Class Codes: A61B 18/02 by cooling, e.g. cryogenic techniques devices for cooling specific reflex points of the body within cell-life limits A61H39/06
• CPC Class Codes: A61B 18/18 by applying electromagnetic radiation, e.g. microwaves radiation therapy A61N5/00
• CPC Class Codes: A61B 2090/365 augmented reality, i.e. correlating a live optical image with another image
• CPC Class Codes: A61B 2090/374 NMR or MRI
• CPC Class Codes: A61B 2090/3954 magnetic, e.g. NMR or MRI
• CPC Class Codes: A61B 34/10 Computer-aided planning, simulation or modelling of surgical operations
• CPC Class Codes: A61B 34/20 Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis
• CPC Class Codes: A61B 5/0044 for the heart
• CPC Class Codes: A61B 5/053 Measuring electrical impedance or conductance of a portion of the body
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: A61B 5/062 using magnetic field
• CPC Class Codes: A61B 5/065 Determining position of the probe employing exclusively positioning means located on or in the probe, e.g. using position sensors arranged on the probe
• CPC Class Codes: A61B 5/283 Invasive
• CPC Class Codes: A61B 5/287 Holders for multiple electrodes, e.g. electrode catheters for electrophysiological study [EPS]
• CPC Class Codes: A61B 5/415 the glands, e.g. tonsils, adenoids or thymus
• CPC Class Codes: A61B 5/418 lymph vessels, ducts or nodes
• CPC Class Codes: A61M 2025/0089 Single injection needle protruding axially, i.e. along the longitudinal axis of the catheter, from the distal tip
• CPC Class Codes: A61M 2025/0166 Sensors, electrodes or the like for guiding the catheter to a target zone, e.g. image guided or magnetically guided
• CPC Class Codes: A61M 2025/0681 Systems with catheter and outer tubing, e.g. sheath, sleeve or guide tube
• CPC Class Codes: A61M 2025/09175 having specific characteristics at the distal tip
• CPC Class Codes: A61M 25/01 : Introducing, guiding, advancing, emplacing or holding catheters A61M25/10 takes precedence
• CPC Class Codes: A61M 25/0127 : Magnetic means; Magnetic markers
• CPC Class Codes: A61M 29/00 : Dilators with or without means for introducing media, e.g. remedies instruments for performing visual medical inspections of cavities or tubes of the body A61B1/00
• CPC Class Codes: A61M 5/00 : Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests vaccination appliances for veterinary use A61D1/025 ; tube connectors, tube couplings, valves or branch units specially adapted for medical use A61M39/00; containers specially adapted for medical or pharmaceutical purposes A61J1/00; combinations of vial and syringe for mixing or transferring their contents A61J1/20; holders for containers for collecting, storing or administering blood or medical fluids A61J1/16
• CPC Class Codes: G01R 33/286 : involving passive visualization of interventional instruments, i.e. making the instrument visible as part of the normal MR process
• CPC Class Codes: G01R 33/287 : involving active visualization of interventional instruments, e.g. using active tracking RF coils or coils for intentionally creating magnetic field inhomogeneities

Abstract

An MRI-compatible catheter that reduces localized heating due to MR scanner-induced currents includes an elongated flexible shaft having a distal end portion and an opposite proximal end portion. A handle is attached to the proximal end portion and includes an electrical connector interface configured to be in electrical communication with an MRI scanner. One or more RF tracking coils are positioned adjacent the distal end portion of the shaft. Each RF tracking coil includes a conductive lead, such as a coaxial cable, that extends between the RF tracking coil and the electrical connector interface and electrically connects the RF tracking coil to an MRI scanner. In some embodiments of the present invention, the conductive lead has a length sufficient to define an odd harmonic/multiple of a quarter wavelength of the operational frequency of the MRI Scanner, and/or includes a series of pre-formed back and forth segments along its length.

Claims

1. An MRI-compatible catheter, comprising:

an elongated flexible shaft having a distal end portion, and an opposite proximal end portion;

an electrical connector interface held by the flexible shaft and configured to be in electrical communication with an MRI scanner;

an ablation tip at the flexible shaft distal end portion, wherein an RF conductor extends longitudinally within the flexible shaft to the electrical connector interface and connects the ablation tip to an RF generator, wherein the RF conductor includes a series of back and forth segments along its length;

at least one RF tracking coil positioned adjacent the distal end portion of the flexible shaft, wherein the at least one tracking coil includes a conductive lead extending between the at least one RF tracking coil and the electrical connector interface and configured to electrically connect the at least one tracking coil to the MRI scanner;

at least one self-resonant cable trap in communication with the at least one RF tracking coil;

at least one sensing electrode at the shaft distal end portion; and

at least one high impedance resistor in communication with the at least one sensing electrode.

2. The catheter of claim 1, wherein the conductive lead includes a series of pre-formed back and forth segments along its length.

3. The catheter of claim 1, wherein the conductive lead is a coaxial cable.

4. The catheter of claim 1, wherein the at least one RF tracking coil comprises a plurality of tracking coils, each attached to a separate conductive lead, and wherein each conductive lead includes a series of back and forth segments along its length.

5. The catheter of claim 1, wherein the at least one self-resonant cable trap comprises an inductor having between about twenty (20) turns and about one-hundred (100) turns.

6. The catheter of claim 1, wherein the conductive lead has a length sufficient to define an odd harmonic/multiple of a quarter wavelength of an operational frequency of the MRI Scanner.

7. The catheter of claim 1, wherein the ablation tip comprises platinum.

8. The catheter of claim 1, wherein the at least one RF tracking coil comprises between 1-10 coil turns.

9. The catheter of claim 1, wherein the at least one RF tracking coil has a length along a longitudinal direction of the catheter of between about 0.25 mm and about 4 mm.

10. The catheter of claim 1, further comprising at least one fluid exit port at the flexible shaft distal end portion, wherein the at least one fluid exit port is in fluid communication with an irrigation lumen that extends longitudinally through the flexible shaft from the at least one fluid exit port.

11. The catheter of claim 1, wherein the at least one RF tracking coil comprises a plurality of tracking coils, each attached to a separate conductive lead, and wherein each conductive lead has a length sufficient to define an odd harmonic/multiple of a quarter wavelength of an operational frequency of the MRI Scanner.

12. The catheter of claim 1, wherein the at least one RF tracking coil is in communication with a circuit configured to stabilize a tracking signal generated by the at least one RF tracking coil.

13. The catheter of claim 12, further comprising a handle attached to the flexible shaft proximal end portion, and wherein the circuit is located within the handle.

14. The catheter of claim 1, further comprising a sheath surrounding at least a portion of the elongated flexible shaft, wherein the sheath includes at least one RF shield coaxially disposed therewithin, the at least one RF shield comprising:

elongated inner and outer conductors, each having respective opposite first and second end portions; and

an elongated dielectric layer of MRI compatible material sandwiched between the inner and outer conductors and surrounding the inner conductor, wherein only the respective first end portions of the inner and outer conductors are electrically connected, and wherein the second end portions are electrically isolated.

15. The catheter of claim 14, wherein the inner and outer conductors comprise conductive foil, conductive braid, or a film with a conductive surface.

16. The catheter of claim 14, wherein the at least one RF shield comprises a plurality of RF shields in end-to-end spaced-apart relationship.

17. The catheter of claim 1, further comprising at least one RF shield coaxially disposed within the flexible shaft, the at least one RF shield comprising:

elongated inner and outer conductors, each having respective opposite first and second end portions; and

an elongated dielectric layer of MRI compatible material sandwiched between the inner and outer conductors and surrounding the inner conductor, wherein only the respective first end portions of the inner and outer conductors are electrically connected, and wherein the second end portions are electrically isolated.

18. The catheter of claim 17, wherein the inner and outer conductors comprise conductive foil, conductive braid, or a film with a conductive surface.

19. The catheter of claim 17, wherein the at least one RF shield comprises a plurality of RF shields in end-to-end spaced-apart relationship.