Magnetic resonance devices suitable for both tracking and imaging

• US 5,715,822 A
• Filed: 09/28/1995
• Issued: 02/10/1998
• Est. Priority Date: 09/28/1995
• Status: Expired due to Term

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Dumoulin, Charles Lucian, Watkins, Ronald Dean
• Primary Examiner(s): Smith, Ruth S.
• Application Number:
  US08/535,695
• Time in Patent Office: 866 Days
• Field of Search: 128/653.2, 128/653.5, 128/899, 324/318, 324/322
• US Class Current: 600/422
• 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
• 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

Abstract

A novel RF coil attached to an invasive device, such as a catheter, is used to detect magnetic resonance (MR) signals for monitoring the position of the device within a subject and for the acquisition of high-resolution magnetic resonance images of the tissue surrounding the device. The novel coil is sensitive to a small volume of MR active tissue during tracking procedures, but is sensitive to a larger volume during imaging procedures. During tracking, the MR signals are detected in the presence of magnetic field gradients and thus have frequencies which are substantially proportional to the location of the coil along the direction of the applied gradient. Signals are detected responsive to applied magnetic gradients to determine the position of the coil in several dimensions. The position of the novel coil, and hence the device, as determined by the tracking system is superimposed upon independently acquired medical diagnostic images. Magnetic Resonance images of the tissue surrounding the novel coil can be obtained by detecting the MR response signals from the novel coil using gradient-recalled, spin-echo or other MR imaging sequences.

Claims

1. A tracking and imaging subsystem for use in a magnetic resonance (MR) imaging device having a calculation device capable of calculating MR source locations and images from MR response signals passed to it comprising:

a) an interventional device intended to be inserted into a subject;

b) an RF coil subsystem having;

i. a plurality of connected winding sections within the interventional device;

ii. a first conductor connected to a first end of the connected winding sections;

iii. a second conductor connected to a second end of the connected winding sections;

iv. at least one conductor between the winding sections;

c) a conductor selector adapted to be coupled to said calculation device for operating in an imaging mode by selecting a pair of conductors based upon a desired field-of-view of an image, and for passing an MR response signal sensed by the winding sections between the selected pair of conductors to said calculation device, the conductor selector capable of also operating in a tracking mode by selecting a plurality of adjacent pairs of conductors, and passing a different MR response signal from each corresponding winding to said calculation device to result in a plurality of tracked locations.

2. The tracking and imaging subsystem recited in claim 1 further comprising:

a superposition device for superimposing a symbol on the image at a position representing the location of said interventional device determined by the calculation device.

3. The tracking and imaging subsystem recited in claim 1, wherein the interventional device comprises one of the group consisting of a guide wire, a catheter, an endoscope, a laparoscope and a biopsy needle.

4. The tracking and imaging subsystem recited in claim 1, wherein the interventional device comprises a surgical implement.

5. The tracking and imaging subsystem recited in claim 1, wherein the interventional device comprises a therapeutic device.

6. The tracking and imaging subsystem recited in claim 1 wherein each of the winding sections has coincident substantially parallel axes through the windings, and are wound in a direction opposite to its adjacent winding section resulting in a coil arrangement with an increased sensitivity perpendicular to the coincident axes.

7. A tracking and imaging subsystem for use in a magnetic resonance (MR) imaging device having an RF transmission device for transmitting energy through connected RF coils, and a calculation device capable of calculating MR source locations and images from MR response signals passed to it comprising:

a) an interventional device intended to be inserted into a subject;

b) an RF coil subsystem having;

i. a plurality of connected winding sections within the interventional device;

ii. a first conductor connected to a first end of the connected winding sections;

iii. a second conductor connected to a second end of the connected winding sections;

iv. at least one conductor between the winding sections;

c) a conductor selector operating in an imaging mode for selecting a pair of conductors corresponding to a desired excitation volume, and for connecting the conductors to the RF transmission device thereby passing energy through the winding sections between the selected pair of conductors, the conductor selector also operating in a tracking mode, for connecting a plurality of adjacent pairs of conductors to the RF transmission device, and for transmitting RF energy through a plurality of winding sections between the selected conductors simultaneously, so as to provide several small point sources capable of being easily tracked.

8. The tracking and imaging subsystem recited in claim 7 wherein each of the winding sections has coincident substantially parallel axes through the windings, and are wound in a direction opposite to its adjacent winding section resulting in a coil arrangement with an increased transmission perpendicular to the coincident axes.

9. The magnetic resonance tracking system recited in claim 7 further comprising:

a superposition device for superimposing a symbol on the image at a position representing the location of said interventional device determined by the calculation device.

10. The tracking and imaging subsystem recited in claim 7, wherein the interventional device comprises one of the group consisting of a guide wire, a catheter, an endoscope, a laparoscope and a biopsy needle.

11. The tracking and imaging subsystem recited in claim 7, wherein the interventional device comprises a surgical implement.

12. The tracking and imaging subsystem recited in claim 7, wherein the interventional device comprises a therapeutic device.