MRI-guided therapy methods and related systems

• US 7,822,460 B2
• Filed: 10/26/2007
• Issued: 10/26/2010
• Est. Priority Date: 11/04/1998
• Status: Expired due to Fees

• Current Assignee: SurgiVision Inc.
• Original Assignee: SurgiVision Inc.
• Inventors: McVeigh, Elliot R., Lima, Joao, Lardo, Albert, Berger, Ronald D., Halperin, Henry R., Atalar, Ergin, Calkins, Hugh
• Primary Examiner(s): Winakur; Eric F
• Assistant Examiner(s): Rozanski; Michael T
• Application Number:
  US11/924,877
• Publication Number:
  US 20080058635A1
• Time in Patent Office: 1,096 Days
• Field of Search: 600/411, 600/421, 600/422, 600/424, 324/307, 324/309, 324/318
• US Class Current: 600/411
• CPC Class Codes: A61B 18/1492 having a flexible, catheter-like structure, e.g. for heart ablation A61B18/1477 takes precedence
• CPC Class Codes: A61B 2017/00039 Electric or electromagnetic phenomena other than conductivity, e.g. capacity, inductivity, Hall effect
• CPC Class Codes: A61B 2017/00053 Mapping
• CPC Class Codes: A61B 2090/374 NMR or MRI
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• 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: A61B 90/36 Image-producing devices or illumination devices not otherwise provided for
• 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 33/4808 Multimodal MR, e.g. MR combined with positron emission tomography [PET], MR combined with ultrasound or MR combined with computed tomography [CT]
• CPC Class Codes: G01R 33/5601 involving use of a contrast agent for contrast manipulation, e.g. a paramagnetic, super-paramagnetic, ferromagnetic or hyperpolarised contrast agent

Abstract

A system and method for using magnetic resonance imaging to increase the accuracy of electrophysiologic procedures is disclosed. The system in its preferred embodiment provides an invasive combined electrophysiology and imaging antenna catheter which includes an RF antenna for receiving magnetic resonance signals and diagnostic electrodes for receiving electrical potentials. The combined electrophysiology and imaging antenna catheter is used in combination with a magnetic resonance imaging scanner to guide and provide visualization during electrophysiologic diagnostic or therapeutic procedures. The invention further provides a system for eliminating the pickup of RF energy in which intracardiac wires are detuned by filtering so that they become very inefficient antennas. An RF filtering system is provided for suppressing the MR imaging signal while not attenuating the RF ablative current. Steering means may be provided for steering the invasive catheter under MR guidance.

Claims

1. A method for performing an MRI-guided medical procedure, comprising the steps of:

placing a subject in a main magnetic field of an MR Scanner;

introducing a single MR-compatible electrode catheter with an MR receive antenna inside the subject while the subject is in the main magnetic field, the MR-compatible electrode catheter comprising at least one electrode and at least one wire coupled to the at least one electrode and extending along the catheter;

generating a plurality of RF pulses using the MR scanner;

attenuating signals induced by the RF pulses in the at least one electrode and the at least one wire coupled to the at least one electrode;

acquiring magnetic resonance signals in response to the RF pulses using the MR receive antenna during and/or after the introducing step;

generating MRI images using the signals acquired by the MR receive antenna;

using the generated MRI images to determine the location of the electrode catheter; and

acquiring electrical signals indicative of an electrophysiological state of target tissue using the at least one electrode while the subject is in the main magnetic field.

2. A method according to claim 1, wherein the generating MRI images step provides the MRI images in substantially real time.

3. A method according to claim 1, wherein the acquiring electrical signals step comprises measuring an electrical potential using the at least one electrode on the electrode catheter.

4. A method according to claim 1, further comprising guiding a mapping procedure with at least one of the generated MRI images.

5. A method according to claim 1, further comprising applying an RF ablative current to the subject from the at least one electrode on the electrode catheter.

6. A method according to claim 1, further comprising attenuating gradient-field-induced noise using at least one active filter.

7. A method according to claim 1, wherein the electrode catheter is sized and configured as a cardiac interventional catheter.

8. A method according to claim 1, wherein the electrode catheter is sized and configured as an intra-brain catheter.

9. A method for performing a medical procedure, comprising the steps of:

placing a subject in a main magnetic field of an MR Scanner;

introducing a single MR-compatible electrode catheter with an MR receive antenna, the MR-compatible electrode catheter comprising at least one electrode and at least one wire coupled to the at least one electrode and extending along the catheter;

generating a plurality of RF pulses using the MR scanner;

attenuating signals induced by the RF pulses in the at least one electrode and the at least one wire coupled to the at least one electrode;

acquiring a magnetic resonance signal in response to the RF pulses using the MR receive antenna;

using magnetic resonance imaging that includes the signal from the MRI receive antenna to determine the location of said MR-compatible electrode catheter;

using said MR-compatible electrode catheter to acquire electrical signals indicative of an electrophysiological state while the subject is in the main magnetic field;

filtering radiofrequency interference from the electrical signals acquired during said step of using the MR-compatible electrode catheter to acquire electrical signals;

ablating tissue to form a lesion using said MR-compatible electrode catheter while the subject is in the main magnetic field; and

visualizing the lesion formed by the ablating step in an MR image using the MR receive antenna of the MR-compatible electrode catheter while the subject is in the main magnetic field.

10. A method according to claim 9, wherein the MR-compatible electrode catheter is a cardiac catheter.

11. A method for performing a medical procedure, comprising the steps of:

placing a subject in a main magnetic field of an MR Scanner;

introducing a single MR-compatible electrode catheter with an MR receive antenna, the MR-compatible electrode catheter comprising at least one electrode and at least one wire coupled to the at least one electrode and extending along the catheter;

generating a plurality of RF pulses using the MR scanner;

attenuating signals induced by the RF pulses in the at least one electrode and the at least one wire coupled to the at least one electrode;

acquiring a magnetic resonance signal in response to the RF pulses using the MR receive antenna;

using magnetic resonance imaging that includes the signal from the MRI receive antenna to determine the location of said MR-compatible electrode catheter;

using said MR-compatible electrode catheter to acquire electrical signals indicative of an electrophysiological state while the subject is in the main magnetic field;

stimulating tissue using said MR-compatible electrode catheter while the subject is in the main magnetic field; and

visualizing the stimulated tissue using the MR receive antenna of the MR-compatible electrode catheter while the subject is in the main magnetic field.

12. A method according to claim 11, wherein the stimulated tissue is cardiac tissue.

13. A method according to claim 11, wherein the stimulated tissue is brain tissue.

14. A MRI interventional system comprising:

an MR Scanner having a main magnetic field; and

an MR-compatible electrode catheter with an MR receive antenna and at least one electrode and at least one wire coupled to the at least one electrode and extending along the catheter, the electrode catheter in communication with the MR Scanner, wherein, in operation, the electrode catheter is configured to;

(a) acquire internal electrical potential and/or electrophysiological signals from a subject during an interventional procedure while the subject is in the main magnetic field;

(b) transmit low frequency excitation or ablation energy to the subject;

(c) attenuate signals induced by RF pulses from the MR Scanner in the at least one electrode and the at least one wire coupled to the at least one electrode; and

(d) receive MR image data signals in response to the RF pulses using the MR receive antenna.

15. An MRI system according to claim 14, further comprising at least one RF filter circuit residing between each electrode and an interface with the MRI scanner, the at least one RF filter configured to attenuate the signals induced by the RF pulses while allowing RF ablative current to be delivered to the at least one electrode.

16. AN MRI system according to claim 15, further comprising one or more active filters coupled to the at least one electrode to attenuate gradient-field-induced noise.

17. An MRI system according to claim 14, wherein the at least one RF filter circuit comprises an inductor and capacitor.

18. An MRI system according to claim 14, wherein the MRI Scanner generates a composite image using signal data from the electrode catheter receive antenna and signal data from an external surface coil, and wherein the MRI Scanner is configured to generate the composite image in substantially real time to prove composite images used during an interventional procedure.