Steady state dark blood magnetic resonance imaging

• US 20100063380A1
• Filed: 09/10/2008
• Published: 03/11/2010
• Est. Priority Date: 09/10/2008
• Status: Active Grant

• Current Assignee: Case Western Reserve University
• Original Assignee: Case Western Reserve University
• Inventors: Griswold, Mark A., Duerk, Jeffrey L., Sunshine, Jeffrey L., Derakhshan, Jamal J.
• Granted Patent: US 8,208,986 B2
• Time in Patent Office: Days
• US Class Current: 600/410
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• 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 33/5607 by reducing the NMR signal of a particular spin species, e.g. of a chemical species for fat suppression, or of a moving spin species for black-blood imaging
• CPC Class Codes: G01R 33/5614 using a fully balanced steady-state free precession [bSSFP] pulse sequence, e.g. trueFISP
• CPC Class Codes: G01R 33/56333 Involving spatial modulation of the magnetization within an imaged region, e.g. spatial modulation of magnetization [SPAMM] tagging perfusion imaging based on arterial spin tagging G01R33/56366

Abstract

Systems, methods, and other embodiments associated with steady state dark blood magnetic resonance imaging MRI are described. One example method includes controlling an MRI apparatus to produce a steady state pulse sequence. The example method may also include controlling the MRI apparatus to generate radio frequency (RF) energy and magnetic gradients associated with the steady state pulse sequence. The steady state pulse sequence is different from conventional steady state pulses in that it is characterized by regularly spaced slice selection excitation pulses to excite a region to be imaged in an object to be imaged using a consistent repetition time (TR), a set of readout modules, and a set of a magnetization preparation modules. A magnetization preparation module is characterized by gradients associated with imaging not being active, gradients associated with slice selection being active, and RF pulses associated with slice selection being active.

Claims

1. A computer-readable medium storing computer-executable instructions that when executed by a computer cause the computer to perform a method, the method comprising:

controlling a magnetic resonance imaging (MRI) apparatus to produce a steady state pulse sequence; and

controlling the MRI apparatus to generate radio frequency (RF) energy and magnetic gradients associated with the steady state pulse sequence;

where the steady state pulse sequence is characterized by;

regularly spaced in time slice selection excitation pulses to excite a region to be imaged in the object to be imaged using a consistent repetition time (TR),

a readout module, and

a magnetization preparation module,

where during a magnetization preparation module a gradient associated with imaging is not active, a gradient associated with slice selection is active, and RF pulses associated with slice selection are active, and

where signals from which an MR image of the object to be imaged can be reconstructed are to be acquired during a readout module.

2. The computer-readable medium of claim 1, where the magnetization preparation module is a saturation module during which the method includes controlling production of a gradient associated with slice selection and RF pulses associated with slice selection to excite a set of saturation regions located outside the region to be imaged.

3. The computer-readable medium of claim 2, where the set of saturation regions includes an even number of regions and where the steady state pulse sequence includes an even number of saturation modules.

4. The computer-readable medium of claim 1, where the method includes controlling the frequency of the magnetization preparation modules to change during acquisition to vary the amount of saturation preparation in relation to the position being encoded in k-space in an adjacent readout module.

5. The computer-readable medium of claim 1, where the steady state pulse sequence includes a repeating pattern comprising an even number of consecutive readout modules followed by an even number of magnetization preparation sequences.

6. The computer-readable medium of claim 5, where the method includes controlling the pulse sequence to apply a relatively larger number of saturation modules when an adjacent readout module is encoding a contrast determining center of k-space and to apply a relatively smaller number of saturation modules when an adjacent readout module is encoding a resolution determining outer region of k-space.

7. The computer-readable medium of claim 1, where the magnetization preparation module is an inversion module.

8. The computer-readable medium of claim 1, where the magnetization preparation module is a tagging module.

9. The computer-readable medium of claim 8, where the method includes controlling, during the tagging module, one or more of, an MR gradient, and RF pulses to produce two different excitations in two different sets of spins, where a first excitation is produced in spins associated with an item that is moving in an imaging region, and where a second excitation is produced in spins that are associated with an item that is substantially static in the imaging region.

10. The computer-readable medium of claim 1, where the steady state pulse sequence is one of, a TrueFISP sequence, a FLASH sequence, a FISP sequence, and a PSIF sequence.

11. The computer-readable medium of claim 1, where the method includes controlling gradients, during a magnetization preparation module, to be anti-symmetric gradients.

12. The computer-readable medium of claim 1, where the magnetization preparation module is configurable with respect to one or more of, the position of a region to be prepared during the magnetization preparation module relative to the region to be imaged, a gap between the region to be prepared during the magnetization preparation and the region to be imaged, and the thickness of a region to be prepared during the magnetization preparation module.

13. The computer-readable medium of claim 1, where the method includes controlling the steady state pulse sequence with respect to the ratio of magnetization preparation modules to readout modules.

14. The computer-readable medium of claim 1, the method comprising:

controlling the MRI apparatus to receive a magnetic resonance (MR) signal from an object to be imaged in response to being exposed to the steady state pulse sequence.

15. The computer-readable medium of claiml4, the method comprising:

controlling the MRI apparatus to reconstruct an MR image from the MR signal and to display the MR image on a display.

16. An apparatus, comprising:

a pulse logic to produce a steady state pulse sequence that includes a set of readout modules and a set of magnetization preparation modules; and

an output logic to produce radio frequency (RF) energy and magnetic gradients associated with the steady state pulse sequence;

where the steady state pulse sequence includes;

regularly spaced in time slice selection excitation pulses to excite a region to be imaged in an object to be imaged using a consistent repetition time (TR),

a readout module, and

a magnetization preparation module,

where during a magnetization preparation module a gradient associated with magnetic resonance (MR) imaging is not active, a gradient associated with slice selection is active, and RF pulses associated with slice selection are active, and

where signal from which an MR image can be reconstructed is to be acquired from the object to be imaged during a readout module.

17. The apparatus of claim 16, comprising:

a reconstruction logic to reconstruct an MR image from signals received from the object to be imaged in response to the steady state pulse sequence.

18. The apparatus of claim 16, the magnetization preparation module being one or more of, a saturation module, an inversion module, and a tagging module.

19. The apparatus of claim 16, the magnetization preparation module being a saturation module during which a gradient associated with region selection and RF pulses associated with region selection are configured to excite a set of saturation regions different from the region to be imaged.

20. A system, comprising:

means for generating a steady state pulse sequence having;

regularly spaced slice selection excitation pulses to excite a region to be imaged in an object to be imaged using a consistent repetition time (TR),

a readout module, and

a magnetization preparation module,

where during a magnetization preparation module a gradient associated with MR imaging is not active, a gradient associated with slice selection is active, and RF pulses associated with slice selection are active, and

where signal from which an MR image can be reconstructed is to be acquired from the object to be imaged during a readout module;

means for applying the steady state pulse sequence to an object to be imaged; and

means for reconstructing a magnetic resonance image from signals acquired from the object to be imaged in response to applying the steady state pulse sequence.