Systems and methods for magnetic resonance imaging

• US 9,770,186 B2
• Filed: 02/19/2013
• Issued: 09/26/2017
• Est. Priority Date: 03/31/2006
• Status: Active Grant

• Current Assignee: National Institutes of Health (NIH) (Government of the United States of America)
• Original Assignee: National Institutes of Health (NIH) (Government of the United States of America)
• Inventors: Jeong, Eun-Kee, Parker, Dennis L, Choi, Kim Seong-Eun, Kholmovski, Evgueni G
• Primary Examiner(s): Santos Rodriguez, Joseph M
• Application Number:
  US13/769,917
• Publication Number:
  US 20130158384A1
• Time in Patent Office: 1,680 Days
• 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 33/5615 Echo train techniques involving acquiring plural, differently encoded, echo signals after one RF excitation, e.g. using gradient refocusing in echo planar imaging [EPI], RF refocusing in rapid acquisition with relaxation enhancement [RARE] or using both RF and gradient refocusing in gradient and spin echo imaging [GRASE]
• CPC Class Codes: G01R 33/5616 using gradient refocusing, e.g. EPI
• CPC Class Codes: G01R 33/56341 Diffusion imaging
• CPC Class Codes: G01R 33/56509 due to motion, displacement or flow, e.g. gradient moment nulling G01R33/567 takes precedence
• CPC Class Codes: G01R 33/56536 due to magnetic susceptibility variations
• CPC Class Codes: G01R 33/5676 Gating or triggering based on an MR signal, e.g. involving one or more navigator echoes for motion monitoring and correction

Abstract

Methods and apparatus for operating an MRI system is provided. The disclosure provides a diffusion-prepared driven-equilibrium preparation for an imaging volume and acquiring 3-dimensional k-space data from said prepared volume by a plurality of echoplanar readouts of stimulated echoes. An excitation radio-frequency signal and first and second inversion RF signals are provided to define a field-of-view (FOV).

Claims

1. A method for interleaved MR imaging, comprising:

performing a preparation sequence comprising;

providing an excitation radio-frequency (RF) signal;

immediately after said excitation RF signal, providing first and second inversion RF signals to define a field-of-view (FOV);

following the preparation sequence, performing an interleaved multi-slice acquisition of the FOV over a sequence of acquisition segments to acquire k-space data, wherein (i) each segment applies an imaging RF pulse to the FOV with a flip angle and (ii) the flip angle is increased over the sequence of the acquisition segments; and

reconstructing one or more images based on the k-space data.

2. The method of claim 1, wherein said first and second inversion RF signals comprise first and second inversion RF pulses.

3. The method of claim 2, wherein said first inversion RF pulse is applied immediately after said excitation RF signal.

4. The method of claim 2, wherein said first and second inversion RF pulses are separated by a time approximately 5 ms or larger.

5. The method of claim 2, wherein said first and second inversion RF pulses are separated by a time less than 5 ms.

6. The method of claim 2, wherein said first and second inversion RF pulses are separated by a time more than 5 ms.

7. The method of claim 2, further comprising providing slice-selective gradients that are selected such that magnetization within said FOV is preserved while magnetization external to said FOV is suppressed, thereby allowing magnetization in each of a plurality of slices to be maintained in its equilibrium state while exciting and imaging one or more others of said plurality of slices.

8. A system for interleaved magnetic resonance imaging (MRI), comprising:

an MRI scanner;

one or more computers configured to generate one or more instructions for;

performing a preparation sequence via the MRI scanner comprising;

providing an excitation radio-frequency (RF) signal;

immediately after said excitation RF signal, providing first and second inversion RF signals to define a field-of-view (FOV); and

following the preparation sequence, performing an interleaved multi-slice acquisition of the FOV via the MRI scanner over a sequence of acquisition segments to acquire k-space data, wherein (i) each segment applies an imaging RF pulse to the FOV with a flip angle and (ii) the flip angle is increased over the sequence of the acquisition segments; and

reconstructing one or more images based on the k-space data.

9. The system of claim 8, wherein said first and second inversion RF signals comprise first and second inversion RF pulses.

10. The system of claim 9, wherein said first inversion RF pulse is applied immediately after said excitation RF signal.

11. The system of claim 9, wherein said first and second inversion RF pulses are separated by a time approximately 5 ms or larger.

12. The system of claim 9, wherein said first and second inversion RF pulses are separated by a time less than 5 ms.

13. The system of claim 9, wherein said first and second inversion RF pulses are separated by a time more than 5 ms.

14. The system of claim 9, wherein said one or more instructions further includes an instruction for providing slice-selective gradients that are selected such that magnetization within said FOV is preserved while magnetization external to said FOV is suppressed, thereby allowing magnetization in each of a plurality of slices to be maintained in its equilibrium state while exciting and imaging one or more others of said plurality of slices.