Flow insensitive magnetization preparation pulse for T2* contrast
First Claim
1. A magnetic resonance imaging method, comprising:
- controlling a magnetic resonance imaging system to generate a magnetization preparation pulse subsequence, wherein the magnetization preparation pulse subsequence includes;
a narrow bandwidth excitation pulse having a duration which is longer than a dephasing time T2* of a short T2* species and which tips spins predominantly of long T2* species out of a longitudinal direction of a main magnetic field while predominantly leaving the short T2* species unaffected,a wide bandwidth spin refocusing pulse having a duration which is shorter than the dephasing time T2* of the short T2* species and which predominantly refocuses the long T2* species and predominantly inverts spins of the short T2* species, anda wide bandwidth restoring pulse having a duration which is shorter than the dephasing time T2* of the short T2* species and which predominantly returns spins of the long T2* species back to the longitudinal direction of the main magnetic field and predominantly tips the spins of the short T2* species out of the longitudinal direction of the main magnetic field,wherein the narrow bandwidth excitation pulse, the wide bandwidth spin refocusing pulse, and the wide-bandwidth restoring pulse all have a same center frequency as each other;
controlling the magnetic resonance imaging system to generate an imaging pulse subsequence to perform magnetic resonance imaging data acquisition following the magnetization preparation pulse subsequence; and
processing, by the magnetic resonance imaging system, the magnetic resonance imaging data,wherein the magnetic resonance imaging data provides blood oxygenation level dependent contrast.
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Abstract
A magnetic resonance system comprises a magnetic resonance scanner (10) including a main magnet (12) generating a static magnetic field biasing nuclear spins toward aligning along a direction of the static magnetic field, magnetic field gradient coils (14), a radio frequency coil (16), and a controller (20, 22) configured to: (a) drive the radio frequency coil to selectively tip spins predominantly of short T2* out of the direction of the static magnetic field; (b) drive at least one of the magnetic field gradient coils and the radio frequency coil to dephase said spins predominantly of short T2* tipped out of the direction of the static magnetic field; and (c) drive the magnetic field gradient coils and the radio frequency coil to acquire magnetic resonance data that is predominantly T2* weighted due to preceding operations (a) and (b).
8 Citations
19 Claims
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1. A magnetic resonance imaging method, comprising:
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controlling a magnetic resonance imaging system to generate a magnetization preparation pulse subsequence, wherein the magnetization preparation pulse subsequence includes; a narrow bandwidth excitation pulse having a duration which is longer than a dephasing time T2* of a short T2* species and which tips spins predominantly of long T2* species out of a longitudinal direction of a main magnetic field while predominantly leaving the short T2* species unaffected, a wide bandwidth spin refocusing pulse having a duration which is shorter than the dephasing time T2* of the short T2* species and which predominantly refocuses the long T2* species and predominantly inverts spins of the short T2* species, and a wide bandwidth restoring pulse having a duration which is shorter than the dephasing time T2* of the short T2* species and which predominantly returns spins of the long T2* species back to the longitudinal direction of the main magnetic field and predominantly tips the spins of the short T2* species out of the longitudinal direction of the main magnetic field, wherein the narrow bandwidth excitation pulse, the wide bandwidth spin refocusing pulse, and the wide-bandwidth restoring pulse all have a same center frequency as each other; controlling the magnetic resonance imaging system to generate an imaging pulse subsequence to perform magnetic resonance imaging data acquisition following the magnetization preparation pulse subsequence; and processing, by the magnetic resonance imaging system, the magnetic resonance imaging data, wherein the magnetic resonance imaging data provides blood oxygenation level dependent contrast. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A magnetic resonance imaging system, comprising:
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a magnetic resonance scanner including a main magnet generating a static, main magnetic field biasing nuclear spins toward aligning along a direction of the static main magnetic field; magnetic field gradient coils; a radio frequency coil; and
a controller configured to;drive the radio frequency coil to generate a magnetization preparation pulse subsequence including; a narrow bandwidth excitation pulse having a duration which is longer than a dephasing time T2* of a short T2* species and which tips spins predominantly of long T2* species out of a longitudinal direction of a main magnetic field while predominantly leaving the short T2* species unaffected, a wide bandwidth spin refocusing pulse having a duration which is shorter than the dephasing time T2* of the short T2* species and which predominantly refocuses the long T2* species and predominantly inverts spins of the short T2* species, and a wide bandwidth restoring pulse having a duration which is shorter than the dephasing time T2* of the short T2* species and which predominantly returns spins of the long T2* species back to the longitudinal direction of the main magnetic field and predominantly tips the spins of the short T2* species out of the longitudinal direction of the main magnetic field, wherein the narrow bandwidth excitation pulse, the wide bandwidth spin refocusing pulse, and the wide-bandwidth restoring pulse all have a same center frequency as each other, and drive the magnetic field gradient coils and the radio frequency coil to acquire magnetic resonance data that is predominantly T2* weighted in response to the magnetization preparation pulse subsequence, wherein acquiring the magnetic resonance data that is predominantly T2* weighted provides blood oxygenation level dependent contrast imaging. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. A magnetic resonance imaging method, comprising:
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controlling a magnetic resonance imaging system to generate a magnetization preparation pulse subsequence, wherein the magnetization preparation pulse subsequence includes; a narrow bandwidth excitation pulse having a duration which is longer than a dephasing time T2* of a short T2* species and which tips spins predominantly of long T2* species out of a longitudinal direction of a main magnetic field while predominantly leaving the short T2* species unaffected, a wide bandwidth spin refocusing pulse having a duration which is shorter than the dephasing time T2* of the short T2* species and which predominantly refocuses the long T2* species and predominantly inverts spins of the short T2* species, and a wide bandwidth restoring pulse having a duration which is shorter than the dephasing time T2* of the short T2* species and which predominantly returns spins of the long T2* species back to the longitudinal direction of the main magnetic field and predominantly tips the spins of the short T2* species out of the longitudinal direction of the main magnetic field; generating, using the magnetic resonance imaging system, an imaging pulse subsequence following the magnetization preparation pulse subsequence; acquiring, using the magnetic resonance imaging system, magnetic resonance imaging data that is predominantly T2* weighted from a human heart produced in response to the magnetization preparation pulse subsequence and the imaging pulse subsequence; and processing the acquired magnetic resonance imaging data to provide blood oxygenation level dependent contrast imaging of the human heart.
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Specification