Magnetic resonance imaging methods for depicting mixtures of chemically shifted and on-resonance moieties
AssigneeDuke University
InventorRaymond Kim
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Abstract
The present disclosure describes, in part, a method for achieving depiction of mixtures of chemically shifted and on-resonance moieties using magnetic resonance imaging (MRI) technology. The method can use a steady-state free precession sequence that can be optimized so that the chemically shifted moiety is in an out-of-phase passband in relation to the on-resonance moiety. This feature can enable detection of tissues with a small amount of the chemically shifted moiety with high sensitivity, including but not limited to detecting fat and water when imaging an organ.
Claims12
A method of magnetic resonance imaging to depict mixtures of chemically shifted and on-resonance moieties depicted in imaging, the method comprising:
- applying a steady-state free precession sequence during operation of a magnetic resonance imaging (MRI) scanner;
- determining a frequency difference between a chemically shifted moiety of a mixture and an on-resonance moiety of the mixture for the MRI scanner;
- calculating an ideal time to repeat (TR) value that centers a peak of the chemically shifted moiety in a passband that is out-of-phase with the on-resonance moiety;
- adjusting a TR value so that it approaches the ideal TR value in view of one or more constraints of the MRI scanner and so it is within an acceptable range of TR values whereby the centered peak of the chemically shifted moiety is a distance in frequency to a nearest passband border at least half that anticipated to be a spread in frequency due to B0 inhomogeneity for a target imaging region;
- and
- acquiring MRI data from the target imaging region after centering the on-resonance peak for the target imaging region.
A method of magnetic resonance imaging to depict mixtures of chemically shifted and on-resonance moieties depicted in imaging, the method comprising:
- applying a steady-state free precession sequence during operation of a magnetic resonance imaging (MRI) scanner;
- determining a frequency difference between a chemically shifted moiety of a mixture and an on-resonance moiety of the mixture for the MRI scanner;
- calculating an ideal time to repeat (TR) value that centers a peak of the chemically shifted moiety in a passband that is in-phase with the on-resonance moiety;
- adjusting a TR value so that it approaches the ideal TR value in view of one or more constraints of the MRI scanner and so it is within an acceptable range of TR values whereby the centered peak of the chemically shifted moiety is a distance in frequency to a nearest passband border at least half that anticipated to be a spread in frequency due to B0 inhomogeneity for a target imaging region;
- and
- acquiring MRI data from the target imaging region after centering the on-resonance peak for the target imaging region.
Dependencies are inferred from the claim text.