Methods for Arbitrary Shape Selective Excitation Summed Spectroscopy and Applications of Same

• US 20090021254A1
• Filed: 07/14/2008
• Published: 01/22/2009
• Est. Priority Date: 07/12/2007
• Status: Active Grant

• Current Assignee: Vanderbilt University
• Original Assignee: Vanderbilt University
• Inventors: DE GRAAF, Robin A., GORE, John C., QIN, Qin
• Granted Patent: US 7,777,488 B2
• Time in Patent Office: Days
• US Class Current: 324/309
• CPC Class Codes: G01R 33/4824 using a non-Cartesian trajectory
• CPC Class Codes: G01R 33/4833 using spatially selective excitation of the volume of interest, e.g. selecting non-orthogonal or inclined slices
• CPC Class Codes: G01R 33/485 based on chemical shift information [CSI] or spectroscopic imaging, e.g. to acquire the spatial distributions of metabolites

Abstract

In another aspect, the present invention relates to a method for NMR measurements of an arbitrarily shaped region of interest of a living subject. In one embodiment, the method comprises the steps of applying a broad bandwidth of RF pulses to the arbitrarily shaped region of interest to obtain a corresponding spectrum, wherein substantially entire range of chemical shifts in the spectrum is excited from the arbitrarily shaped region of interest, interleaving a plurality of radial k-lines in radial k-space per excitation with non-selective refocusing pulses and obtaining spatial localization for the spectrum of the arbitrarily shaped region of interest.

Claims

1. A method for NMR measurements of an arbitrarily shaped region of interest of a living subject, comprising the steps of:

(a) applying a broad bandwidth of RF pulses to the arbitrarily shaped region of interest to obtain a corresponding spectrum, wherein substantially entire range of chemical shifts in the spectrum is excited from the arbitrarily shaped region of interest;

(b) interleaving a plurality of radial k-lines in radial k-space per excitation with non-selective refocusing pulses; and

(c) obtaining spatial localization for the spectrum of the arbitrarily shaped region of interest.

2. The method of claim 1, wherein the plurality of radial k-lines in radial k-space has a total number N_k-line.

3. The method of claim 2, wherein the total number N_k-line is an odd number.

4. The method of claim 2, wherein the total number N_k-line=1, 5 or 9.

5. The method of claim 1, wherein the arbitrarily shaped region of interest is two dimensional.

6. The method of claim 1, wherein the arbitrarily shaped region of interest is three dimensional.

7. A system for NMR measurements of an arbitrarily shaped region of interest of a living subject, comprising:

(a) means for applying a broad bandwidth of RF pulses to the arbitrarily shaped region of interest to obtain a corresponding spectrum, wherein substantially entire range of chemical shifts in the spectrum is excited from the arbitrarily shaped region of interest;

(b) means for interleaving a plurality of radial k-lines in radial k-space per excitation with non-selective refocusing pulses; and

(c) means for obtaining spatial localization for the spectrum of the arbitrarily shaped region of interest.

8. The system of claim 7, wherein the plurality of radial k-lines in radial k-space has a total number N_k-line.

9. The system of claim 8, wherein the total number N_k-line=1, 5 or 9.

10. The system of claim 8, wherein the total number N_k-line is an odd number.

11. The system of claim 7, further comprising means for generating a broad bandwidth of RF pulses.

12. A method for NMR measurements of an arbitrarily shaped region of interest of a living subject, comprising the steps of:

(a) applying RF pulses with a bandwidth to the arbitrarily shaped region of interest to obtain a corresponding spectrum with one or more excitations;

(b) interleaving a plurality of radial k-lines in radial k-space per excitation with one or more non-selective refocusing pulses; and

(c) obtaining spatial localization for the spectrum of the arbitrarily shaped region of interest.

13. The method of claim 12, wherein the bandwidth of the RF pulses is sufficiently broad to allow a substantially entire range of chemical shifts in the spectrum to be excited from the arbitrarily shaped region of interest.

14. The method of claim 13, wherein the frequency of the RF pulses is in the range of 10 Hz to 100 GHz.

15. The method of claim 14, wherein the bandwidth of one or more refocusing pulses is in the range of 10 Hz to 100 GHz but the frequency of one or more refocusing pulses is different from that of corresponding RF pulses.

16. The method of claim 12, wherein the plurality of radial k-lines in radial k-space has a total number N_k-line.

17. The method of claim 16, wherein the total number N_k-line is an odd number.

18. The method of claim 16, wherein the total number N_k-line=1, 5 or 9.

19. The method of claim 12, wherein the arbitrarily shaped region of interest is two dimensional.

20. The method of claim 12, wherein the arbitrarily shaped region of interest is three dimensional.