Functional Magnetic Resonance Imaging (fMRI) Methodology Using Transverse Relaxation Preparation and Non-Echo-Planar Imaging (EPI) Pulse Sequences

• US 20160113501A1
• Filed: 06/03/2014
• Published: 04/28/2016
• Est. Priority Date: 06/03/2013
• Status: Abandoned Application

• Current Assignee: Johns Hopkins University, Kennedy Krieger Institute
• Original Assignee: Johns Hopkins University, Kennedy Krieger Institute
• Inventors: Hua, Jun, Jones, Craig Kenneth, Qin, Qin, VanZijl, Peter
• Application Number:
  US14/895,609
• Publication Number:
  US 20160113501A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 2576/026 for the brain
• CPC Class Codes: A61B 5/0042 for the brain
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: G01R 33/4806 Functional imaging of brain activation
• CPC Class Codes: G01R 33/5602 by filtering or weighting based on different relaxation times within the sample, e.g. T1 weighting using an inversion pulse
• CPC Class Codes: G01R 33/5617 using RF refocusing, e.g. RARE
• CPC Class Codes: G16H 30/40 for processing medical images, e.g. editing

Abstract

An embodiment in accordance with the present invention provides a new acquisition scheme for T2-weighted BOLD fMRI. It employs a T2 preparation module to induce the BOLD contrast, followed by a single-shot 3D fast gradient echo (GRE) readout with short echo time (TE<2 ms). The separation of BOLD contrast generation from the readout substantially reduces the “dead time” due to long TE required in spin echo (SE) BOLD sequences. This approach termed “3D T2prep-GRE,” can be implemented with any magnetic resonance imaging machine, known to or conceivable by one of skill in the art. This approach is expected to be useful for ultra-high field fMRI studies that require whole brain coverage, or focus on regions near air cavities. The concept of using T2 preparation to generate BOLD contrast can be combined with many other fast imaging sequences at any field strength.

Claims

1. A method for magnetic resonance imaging of a subject comprising:

employing a T2-weighted preparation module to induce blood-oxygenation-level-dependent (BOLD) contrast;

providing a single-shot, fast-gradient echo (GRE) readout; and

acquiring an image of the subject.

2. The method of claim 1 further comprising providing the single-shot fast-GRE readout having a short echo time.

3. The method of claim 2 further comprising using the short echo time of approximately <

2 ms.

4. The method of claim 1 further comprising using the single shot fast-GRE readout taking the form of at least one of turbo field echo, TFE, or turbo flash.

5. The method of claim 1 further comprising acquiring the image further comprising a whole brain fMRI image with minimal distortion and dropouts.

6. The method of claim 5 further comprising acquiring the image further comprising a spatial resolution of approximately 2.5 mm isotropic.

7. The method of claim 5 further comprising acquiring the image comprising a temporal resolution of 2.3 s at 7 T.

8. The method of claim 1 further comprising generating the BOLD contrast before providing the single-shot, fast GRE readout.

9. The method of claim 1 further comprising using two 180°

pulses in the T2-weighted preparation module to compensate for phase variations and to suppress inflow effects.

10. The method of claim 1 further comprising playing a spoiler gradient at an end of the T2-weighted preparation module on a first phase encoding axis that has a lowest gradient duty cycle to dephase any residual transverse magnetization.

11. The method of claim 1 further comprising using a SINC RF pulse for refocusing.

12. The method of claim 1 further comprising using the single-shot fast-gradient echo readout comprising low-high (centric) phase encoding.

13. A system for magnetic resonance imaging comprising:

a magnetic resonance imaging scanner;

a non-transitory computer readable medium programmed to execute steps comprising;

employing a T2-weighted preparation module to induce blood-oxygenation-level-dependent (BOLD) contrast;

providing a single-shot, fast-gradient echo (GRE) readout; and

acquiring an image of the subject.

14. The system of claim 13 wherein the non-transitory computer readable medium is integrated into the magnetic resonance imaging scanner.

15. The system of claim 13 wherein the non-transitory computer readable medium resides on a computing device networked with the magnetic resonance imaging scanner.

16. The system of claim 13 further comprising the single-shot fast-GRE having a short echo time.

17. The system of claim 16 wherein the short echo time is approximately <

2 ms.

18. The system of claim 13 wherein the single shot fast-GRE takes the form of at least one of turbo field echo, TFE, or turbo flash.

19. The system of claim 13 wherein the image further comprises a whole brain fMRI image with minimal distortion and dropouts.

20. The system of claim 19 wherein the image further comprises a spatial resolution of approximately 2.5 mm isotropic.

21. The system of claim 19 wherein the image comprises a temporal resolution of 2.3 s at 7 T.

22. The system of claim 13 wherein the BOLD contrast is generated before providing the single-shot, fast GRE readout.

23. The system of claim 13 further comprising using two 180°

pulses in the T2-weighted preparation module to compensate for phase variations and to suppress inflow effects.

24. The system of claim 13 further comprising playing a spoiler gradient at an end of the T2-weighted preparation module on a first phase encoding axis that has a lowest gradient duty cycle to dephase any residual transverse magnetization.

25. The system of claim 13 further comprising using a SINC RF pulse for refocusing.

26. The system of claim 13 further comprising using the single-shot fast-gradient echo readout comprising low-high (centric) phase encoding.