INTERVENTION-INDEPENDENT SCAN PLANE CONTROL FOR MRI

• US 20120053448A1
• Filed: 09/01/2010
• Published: 03/01/2012
• Est. Priority Date: 09/01/2010
• Status: Active Grant

• Current Assignee: Case Western Reserve University
• Original Assignee: Case Western Reserve University
• Inventors: GRISWOLD, Mark A., GULANI, Vikas, RIFFE, Matthew, YUTZY, Stephen, NAKAMOTO, Dean, HSU, Daniel
• Granted Patent: US 9,066,673 B2
• Time in Patent Office: Days
• US Class Current: 600/411
• CPC Class Codes: A61B 2034/2051 Electromagnetic tracking systems
• CPC Class Codes: A61B 2090/364 Correlation of different images or relation of image positions in respect to the body
• CPC Class Codes: A61B 2090/374 NMR or MRI
• CPC Class Codes: A61B 34/76 Manipulators having means for providing feel, e.g. force or tactile feedback
• 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 5/721 using a separate sensor to detect motion or using motion information derived from signals other than the physiological signal to be measured

Abstract

Example systems, apparatus, circuits, and so on described herein concern intervention-independent scan plane control for an MRI system. A tracking device capable of being manipulated independently of an interventional device in use to treat a patient transmits position signals describing an orientation of the tracking device to an MRI system. The MRI system determines a desired scan plan that will correspond to the orientation of the tracking device and performs a diagnostic scan on the desired scan plan.

Claims

1. An apparatus, comprising:

a plurality of markers configured to produce position signals corresponding to positions of the markers, where the position signals are sufficient to describe a desired magnetic resonance (MR) scan plane;

one or more transmitters configured to transmit the position signals to a magnetic resonance imaging ((MRI) system;

where the markers and transmitters operate without signal or mechanical interaction with an interventional device in use to treat a patient; and

where the desired scan plan controls the MRI system to perform a subsequent scan of the patient independent of a position of the interventional device in use to treat the patient.

2. The apparatus of claim 1, the interventional device being one of, a needle, a catheter, a diagnostic device, and a therapeutic device.

3. The apparatus of claim 1, where the markers comprise active tracking markers that are responsive to excitation from the MRI magnetic field to produce the position signals.

4. The apparatus of claim 1, where the markers comprise a fiducial marker coupled to a microcoil.

5. The apparatus of claim 3, where the microcoil comprises a gradiometer.

6. The apparatus of claim 1, where the one or more transmitters are configured to transmit the position signals wirelessly to the MRI system using one or more of, amplitude modulation, and frequency modulation.

7. The apparatus of claim 1, where the position signals control the MRI system to display one or more of, the interventional device, anatomy in proximity to the interventional device, and a target.

8. The apparatus of claim 1, comprising a wireless tracing device reference recovery unit configured to receive a mixed signal comprising high frequency upper and lower sideband components of a low frequency reference signal and to mix the received high frequency components upper and lower sideband components to recover the low frequency reference signal, where the reference signal is used to synchronize the apparatus with the MRI system for wireless communication.

9. The apparatus of claim 1, comprising three markers having a non-uniform spacing with respect to one another.

10. The apparatus of claim 1, comprising a housing configured to be held in hand, where the housing encloses the markers and transmitters.

11. The apparatus of claim 1, comprising an onboard asynchronous reference source configured to produce a reference signal asynchronous to a synchronization signal associated with the MRI system.

12. The apparatus of claim 11, the onboard asynchronous reference source being a ceramic oscillator having an oscillation frequency in the range of 5 MHz to 10 MHz and configured to produce the reference signal with a frequency shift error in the range of 1 ppm to 100 ppm.

13. The apparatus of claim 11, the onboard asynchronous reference source being configured to produce a carrier frequency to facilitate transmitting the position signals.

14. A method comprising:

receiving, from a tracking device being manipulated independently of an interventional device in use to treat a patient, position signals describing an orientation of the tracking device;

determining a scan plan that will correspond to the orientation of the tracking device; and

controlling an MRI system to perform a scan on the determined scan plan.

15. The method of claim 14, the interventional device being one of, a needle, a catheter, a diagnostic device, an imaging device, and a therapeutic device.

16. The method of claim 14, where the receiving is performed wirelessly.

17. The method of claim 14, where the receiving is performed by wirelessly receiving one or more of, amplitude modulated signals describing an orientation of the tracking device, and frequency modulated signals describing an orientation of the tracking device.

18. The method of claim 14, comprising controlling the MRI system to display one or more of, the interventional device, anatomy in proximity to the interventional device, and a target.

19. The method of claim 14, where the received position signals are generated by a plurality of markers housed within the tracking device and where determining the scan plane is performed by:

collecting image data including tracking projections in three orthogonal axes for each marker;

performing Fourier transform operations on the tracking projection in each axis;

determining a position with respect to each axis for the markers using magnitude reconstruction on the output of the Fourier transform operations; and

constructing a scan plane that intersects the determined positions of the markers.

20. The method of claim 14, where the receiving of position signals is performed wirelessly and further comprising wirelessly receiving a reference signal for use in synchronizing the position signals from the tracking device with the MRI system.

21. The method of claim 20, where the receiving of a reference signal comprises:

receiving a mixed signal comprising high frequency upper and lower side band frequencies for a low frequency reference signal; and

reconstructing the low frequency reference signal by mixing the upper and lower side band frequencies of the mixed signal.

22. The method of claim 21, where the upper side band frequency and the lower side band frequency are higher than the frequency of a detected MRI signal.

23. An MRI system, comprising:

an MRI apparatus that performs a scan of a patient along a scan plane;

an MRI control unit configured to control the MRI apparatus to perform the scan of the patient along the scan plane;

a tracking device configured to be manipulated by an interventionalist without mechanical or signal interaction with an interventional device being applied to patient, the tracking device being further configured to transmit position signals corresponding to an interventionalist controlled orientation of the tracking device to the MRI control unit; and

where the MRI control unit converts the position signals into a scan plan that coincides with the orientation of the tracking device and controls the MRI apparatus to perform a subsequent scan along the scan plane.

24. The MRI apparatus of claim 23, where the tracking device comprises:

a housing configured to be held in hand and to be manipulated without mechanical or signal interaction with an interventional device used to treat a patient;

a plurality of active tracking markers that are responsive to excitation from the MRI magnetic field positioned within the housing configured to produce position signals corresponding to positions of the markers, where the position signals are sufficient to describe a desired scan plane; and

one or more of transmitters positioned within the housing and configured to wirelessly transmit the position signals to the MRI control unit.

25. The MRI apparatus of claim 23, where the one or more transmitters are configured to transmit the position signals wirelessly to the MRI control unit using amplitude modulation.

26. The MRI apparatus of claim 23, where the one or more transmitters are configured to transmit the position signals wirelessly to the MRI control unit using frequency modulation.

27. The MRI apparatus of claim 23, where the tracking device comprises an asynchronous reference signal source configured to produce a reference signal asynchronous to a synchronization signal associated with the MRI apparatus, and where the one or more transmitters are configured to transmit the position signals based, at least in part, on the asynchronous reference signal.

28. The MRI apparatus of claim 27, the asynchronous reference signal source being a 5 MHz ceramic oscillator configured to produce a reference signal with a frequency shift error less than 20 ppm.

29. The MRI apparatus of claim 28, the ceramic oscillator being a 10 MHz oscillator configured to produce a reference signal with a frequency shift error less than 100 ppm.

30. The MRI apparatus of claim 24, where the MRI control unit converts the position signals into the scan plane by:

collecting projection Fourier transforms in three axes for the plurality of active tracking markers;

determining a position with respect to each axis for the active tracking markers using magnitude reconstruction; and

constructing a scan plane the intersects the determined position of the active tracking markers.

31. An apparatus comprising;

means for defining a desired scan plane, the means for defining being hand held; and

means for transmitting the desired scan plane to an MRI imaging system, the means for transmitting being hand held;

where the desired scan plan is used by the MRI imaging system to perform a subsequent scan of the patient independent of a position of an interventional device in use to treat a patient.

32. A method comprising:

receiving tactile feedback from an interventional device in use on a patient; and

in response to the tactile feedback, manipulating a hand held tracking device to specify a desired scan plane for an MR image, where the manipulation of the hand held tracking device is performed without mechanical or signal interaction with the interventional device.

33. An apparatus for use in the bore of an MRI system that controls one or more elements using a synchronization signal, comprising:

an onboard asynchronous reference source configured to produce a reference signal asynchronous to the synchronization signal, and

a logic controlled by the reference signal.

34. The apparatus of claim 33, the onboard asynchronous reference source being a 5 MHz ceramic oscillator configured to produce the reference signal with a frequency shift error of less than 20 ppm.

35. The apparatus of claim 33, the onboard asynchronous reference source being a 10 MHz ceramic oscillator configured to produce the reference signal with a frequency shift error of less than 100 ppm.

36. The apparatus of claim 33, the onboard asynchronous reference source being a ceramic oscillator in the range of a 1 MHz oscillator to a 100 MHz oscillator.

37. The apparatus of claim 36, the onboard asynchronous reference source being configured to produce the reference signal with a frequency shift error of less than 200 ppm.

38. The apparatus of claim 34, the onboard asynchronous reference source being configured to produce a carrier frequency to facilitate transmitting one or more signals rom the apparatus to the MRI system.