MAGNETIC RESONANCE THERMOMETRY USING PRF SPECTROSCOPY

• US 20120071746A1
• Filed: 09/21/2011
• Published: 03/22/2012
• Est. Priority Date: 09/21/2010
• Status: Abandoned Application

• Current Assignee: InSightec Ltd.
• Original Assignee: InSightec Ltd.
• Inventors: Vortman, Kobi, Freundlich, David, Vitek, Shuki
• Application Number:
  US13/238,743
• Publication Number:
  US 20120071746A1
• Time in Patent Office: Days
• US Class Current: 600/411
• CPC Class Codes: G01R 33/4804 Spatially selective measurement of temperature or pH
• CPC Class Codes: G01R 33/4814 MR combined with ultrasound

Abstract

During the thermal treatment of an anatomical zone of interest, tissue temperature within the zone may be determined with a computational model whose parameters are adjusted using spectroscopy-based temperature measurements at interfaces of fat and non-fat tissues.

Claims

1. A method of performing spectroscopy-based magnetic resonance (MR) temperature measurement, the method comprising the steps of:

acquiring spectroscopy-based temperature measurements in defined regions along an interface of an anatomic zone of interest;

using a prediction model, computationally predicting the temperature in the defined interface regions;

adjusting the prediction model based on the temperature measurements; and

computationally generating a temperature map of the zone of interest using the adjusted prediction model.

2. The method of claim 1 wherein the interface separates fatty and non-fatty tissue.

3. The method of claim 1 wherein the interface comprises a boundary of the anatomic zone of interest.

4. The method of claim 3 wherein the boundary separates non-fatty tissue from a fat-containing gel pad.

5. The method of claim 3 wherein the boundary separates tissue from a partially fatty gel pad.

6. The method of claim 1 wherein adjusting the prediction model comprises adjusting variable parameters of the prediction model.

7. The method of claim 6 wherein the variable parameters comprise tissue parameters.

8. The method of claim 6 wherein the tissue parameters comprise at least one of a perfusion coefficient, a thermal absorption coefficient, or a metabolic heat generation rate.

9. The method of claim 1 wherein the prediction model is based on a bioheat transfer equation.

10. The method of claim 9 wherein the bioheat transfer equation is the Pennes equation.

11. The method of claim 9 wherein generating the temperature map comprises numerically solving the bioheat transfer equation.

12. The method of claim 1 wherein the prediction model comprises an analytical temperature profile over the zone of interest.

13. The method of claim 12 wherein adjusting the prediction model comprises fitting the analytical temperature profile to the temperature measurements.

14. The method of claim 1 further comprising subjecting at least a portion of the zone of interest to a temperature-affecting stimulus.

15. The method of claim 14 wherein the stimulus comprises acoustic energy applied to tissue within the zone of interest.

16. The method of claim 15 wherein the tissue includes tissue within at least one of a focal zone, a near field, or a far field.

17. The method of claim 14 wherein the stimulus comprises cooling applied to a boundary of the zone of interest.

18. The method of claim 1 wherein the defined regions are volumes spanning fatty and non-fatty material.

19. The method of claim 18 wherein the volumes are sufficiently small that a temperature variation through the volumes is not clinically significant.

20. The method of claim 18 wherein the spectroscopy-based temperature measurements comprise measurements of the proton resonance frequencies in the fatty and non-fatty materials.

21. The method of claim 1 further comprising using the temperature map as a baseline for proton-resonance-frequency-shift-based temperature measurements within the zone of interest.

22. A system for performing spectroscopy-based magnetic resonance (MR) temperature measurement, the system comprising:

(a) an MRI unit for acquiring spectroscopy-based temperature measurements in defined regions along an interface of an anatomic zone of interest;

(b) a storage unit for storing a prediction model and parameters associated therewith;

(c) a computer, in communication with the MRI unit, configured to;

predict, using the prediction model, the temperature in the defined interface regions;

adjust the stored parameters of the prediction model based on the temperature measurements; and

generate, using the prediction model and the adjusted parameters, a temperature map of the zone of interest.

23. The system of claim 22 further comprising a display for displaying the temperature map.

24. The system of claim 22 wherein the computer is further configured to cause a thermal-treatment device to subject at least a portion of the zone of interest to heat.

25. The system of claim 24 wherein the thermal-treatment device comprises an ultrasound transducer.

26. The system of claim 22 wherein the computer is further configured to cause a cooling system to subject at least a portion of a boundary of the zone of interest to cooling.

27. The system of claim 22 wherein the interface comprises a boundary of the zone of interest, the system further comprising a fat-containing gel pad for placement against the boundary.