Method for differentiating tissues in magnetic resonance imaging

• US 7,634,302 B2
• Filed: 07/09/2004
• Issued: 12/15/2009
• Est. Priority Date: 07/09/2004
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Gupta, Rakesh Kumar, Rao, Anasuya Mohan, Venkatesan, Ramesh
• Primary Examiner(s): Casler; Brian
• Assistant Examiner(s): Shahrestani; Nasir
• Application Number:
  US10/888,600
• Publication Number:
  US 20060020197A1
• Time in Patent Office: 1,985 Days
• Field of Search: 600407-480, 324/307, 324/309, 324/310
• US Class Current: 600/410
• CPC Class Codes: G01R 33/4824 using a non-Cartesian trajectory
• CPC Class Codes: G01R 33/5605 by transferring coherence or polarization from a spin species to another, e.g. creating magnetization transfer contrast [MTC], polarization transfer using nuclear Overhauser enhancement [NOE]
• CPC Class Codes: G01R 33/5616 using gradient refocusing, e.g. EPI
• CPC Class Codes: G01R 33/5617 using RF refocusing, e.g. RARE
• CPC Class Codes: G01R 33/56341 Diffusion imaging
• CPC Class Codes: G01R 33/56366 Perfusion imaging

Abstract

A method of differentiating tissues in Magnetic Resonance Imaging (MRI) comprising applying a Magnetization Transfer (MT) pre-pulse in combination with the Diffusion Weighted Imaging (DWI) pulse sequence to obtain an image of the tissue under evaluation. Analysis maps and/or measurements are generated from the obtained image, from which values representative of the macromolecular content are computed for obtaining tissue differentiation.

Claims

1. A method comprising:

applying a magnetization transfer pre-pulse in combination with a diffusion weighted imaging pulse sequence that is a diffusion tensor imaging sequence to produce an image of a tissue under evaluation, the applying further comprising applying diffusion gradient along a plurality of orthogonal directions selected from a group consisting of two orthogonal directions and three orthogonal directions;

generating analysis maps, being apparent diffusion coefficient maps representative of cell density and viscosity of tissue, and measurements from the produced image; and

computing values representative of the macromolecular content of the tissue from the map and measurements, wherein the magnetization transfer pre-pulse suppresses signals from water that is bound to macromolecules.

2. The method according to claim 1 wherein the magnetization transfer pre-pulse comprises an off-resonance Fermi pulse.

3. The method according to claim 1 wherein the magnetization transfer pre-pulse comprises an off-resonance sinc pulse.

4. The method according to claim 1 wherein the magnetization transfer pre-pulse is a binomial pulse.

5. The method according to claim 2 wherein the duration of the magnetization transfer pre-pulse is about 2 to 32 ms.

6. The method according to claim 5 wherein the duration of the magnetization transfer pre-pulse is about 16 ms.

7. The method according to claim 5 wherein the duration of the magnetization transfer pre-pulse is about 8 ms.

8. The method according to claim 2 wherein the flip angle of the magnetization transfer pre-pulse is about 600 to 1100 deg.

9. The method according to claim 8 wherein the flip angle of the magnetization transfer pre-pulse is about 670 deg.

10. The method according to claim 2 wherein the resonance offset of the magnetization transfer pre-pulse is about 400 to 1600 Hz.

11. The method according to claim 10 wherein the resonance offset of the magnetization transfer pre-pulse is about 1200 Hz.

12. The method according to claim 1 wherein the diffusion weighted imaging pulse sequence is a diffusion-weighted echo planar imaging pulse sequence.

13. The method according to claim 1 wherein the diffusion weighted imaging pulse sequence is a single shot diffusion-weighted fast spin echo pulse sequence.

14. The method according to claim 1 wherein the diffusion weighted imaging pulse sequence is a diffusion weighted propeller imaging sequence.

15. The method according to claim 1 wherein the diffusion weighted imaging pulse sequence is a fluid attenuated inversion recovery pulse sequence.

16. The method according to claim 1 wherein the applied magnetization transfer pre-pulse is shaped to have a Fermi envelope.

17. The method according to claim 1 further comprising applying diffusion gradients along three orthogonal directions.

18. The method according to claim 1 wherein the tissue has a substantially high concentration of neurotransmitters.

19. The method according to claim 1 wherein the tissue is afflicted with tumors.

20. The method according to claim 1 wherein the tissue is afflicted with abscesses.

21. The method according to claim 1 wherein the tissue is afflicted with cysts.

22. The method according to claim 1 wherein the tissue is associated with psychiatric disorders.

23. The method according to claim 1 wherein the tissue is associated with normal brain parenchyma.

24. The method according to claim 22 wherein the disorders include one or more from the group consisting of schizophrenia, unipolar depression, bipolar depression, conversion disorders and dissociative convulsions.

25. The method according to claim 1 wherein the image is produced using a tracer-free tissue differentiation in vivo.

26. The method according to claim 22 wherein the image of the tissue is produced for at least one of diagnosis, treatment, evaluation of drug efficacy and follow-up.

27. A method comprising:

applying a magnetization transfer pre-pulse in combination with a diffusion weighted imaging pulse sequence that is a diffusion tensor imaging sequence to produce an image of a tissue under evaluation, the applying further comprising applying diffusion gradients along a plurality of orthogonal directions selected from a group consisting of two orthogonal directions and three orthogonal directions;

generating analysis maps, being apparent diffusion coefficient maps, and measurements from the produced image wherein the obtained analysis maps and measurements are used for fiber tractography and elucidation of white matter tracts; and

computing values representative of the macromolecular content of the tissue from the map and measurements, wherein the magnetization transfer pre-pulse suppresses signals from water that is bound to macromolecules.