Magnetic-resonance-guided imaging, electrophysiology, and ablation

• US 6,701,176 B1
• Filed: 10/29/1999
• Issued: 03/02/2004
• Est. Priority Date: 11/04/1998
• Status: Expired due to Term

• Current Assignee: Johns Hopkins University
• Original Assignee: Johns Hopkins University
• Inventors: Berger, Ronald D., McVeigh, Elliot R., Calkins, Hugh, Lima, Joao, Lardo, Albert, Halperin, Henry R., Atalar, Ergin
• Primary Examiner(s): Jaworski, Francis J.
• Assistant Examiner(s): SHAW, SHAWNA JEANNINE
• Application Number:
  US09/428,990
• Time in Patent Office: 1,586 Days
• Field of Search: 600/424, 600/300, 600/410, 600/411, 600/422, 600/423, 606/158, 606/33, 128/898, 128/899, 324/307
• 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 is particularly applicable to catheter ablation, e.g., ablation of atrial fibrillation. In embodiments which are useful for catheter ablation, the combined electrophysiology and imaging antenna catheter may further include an ablation tip, and such embodiment may be used as an intracardiac device to both deliver energy to selected areas of tissue and visualize the resulting ablation lesions, thereby greatly simplifying production of continuous linear lesions. The invention further includes embodiments useful for guiding electrophysiologic diagnostic and therapeutic procedures other than ablation. Imaging of ablation lesions may be further enhanced by use of MR contrast agents. The antenna utilized in the combined electrophysiology and imaging catheter for receiving MR signals is preferably of the coaxial or “loopless” type. High-resolution images from the antenna may be combined with low-resolution images from surface coils of the MR scanner to produce a composite image. 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. Other ablative methods can be used such as laser, ultrasound, and low temperatures.

Claims

1. A method for performing an imaging procedure, comprising the steps of:

placing a subject in a main magnetic field;

introducing an invasive imaging antenna or coil;

acquiring a first magnetic resonance image from said invasive imaging antenna or coil;

acquiring a second magnetic resonance image from a surface coil; and

combining said first and second magnetic resonance images to produce a composite image.

2. The method according to claim 1, further comprising constructing a three-dimensional rendering of the heart from the composite image.

3. The method according to claim 2, further comprising the step of storing said three-dimensional rendering into a texture map of an imaging volume.

4. The method of claim 1, further comprising generating an RF magnetic resonance imaging signal.

7. The method of claim 1, further comprising guiding an ablation procedure with the composite image.

8. The method of claim 7, wherein the ablation procedure comprises ablating atrial tissue.

9. The method of claim 7, wherein the ablation procedure comprises ablating a cardiac arrhythmia.

10. The method of claim 7, wherein the ablation procedure comprises ablating a tumor.

11. The method of claim 1, further comprising guiding a mapping procedure with the composite image.

12. The method of claim 1, further comprising constructing a three-dimensional map of tissue with the composite image.

13. The method of claim 1, further comprising positioning an electrode to measure an electrical potential with guidance from the composite image.

14. The method of claim 1, further comprising guiding a thermal imaging procedure with the composite image.

15. The method of claim 1, further comprising locating at ablation lesion on at least one of the first magnetic resonance image, the second magnetic resonance image, and the composite image.

16. The method of claim 1, further comprising locating the invasive imaging antenna or coil with at least one of the first magnetic resonance image, the second magnetic resonance image, and the composite image.

17. The method according to claim 1, further comprising introducing a magnetic resonance contrast agent to enhance at least one of the first magnetic resonance image, the second magnetic resonance image, and the composite image.

5. The method of claim 5, further comprising generating an RF ablative current.

6. The method of claim 5, further comprising filtering a magnetic resonance imaging signal from the RF ablative current.

18. A system for performing an imaging procedure, comprising:

an invasive magnetic resonance imaging antenna or coil;

means for acquiring a first magnetic resonance image from said invasive imaging antenna or coil;

means for acquiring a second magnetic resonance image from a surface coil; and

means for combining said first and second magnetic resonance images to produce a composite image.

19. The system according to claim 18, further comprising means for constructing a three-dimensional rendering of the heart from the composite image.

20. The system according to claim 19, further comprising means for storing said three-dimensional rendering into a texture map of an imaging volume.

21. The system of claim 18, further comprising means for generating an RF magnetic resonance imaging signal.

22. The system of claim 18, further comprising means for generating an RF ablative current.

23. The system of claim 22, wherein said means for generating an RF ablative current is integral with said invasive magnetic resonance imaging coil.

24. The system of claim 22, further comprising means for filtering a magnetic resonance imaging signal from the RF ablative current.

25. The system of claim 18, further comprising means for guiding a mapping procedure with the composite image.

26. The system of claim 18, further comprising means for constructing a three-dimensional map of tissue with the composite image.

27. The system of claim 18, further comprising means for measuring an electrical potential.

28. The system of claim 27, wherein said means for measuring an electrical potential is integral with said invasive magnetic resonance imaging coil.