SYSTEMS AND METHODS FOR STRATEGICALLY ACQUIRED GRADIENT ECHO IMAGING
First Claim
1. A magnetic resonance imaging (MRI) system comprising:
- a MRI scanner configured to acquire a first magnetic resonance (MR) dataset corresponding to a first flip angle and a second MR dataset corresponding to a second flip angle by imaging an anatomical region using at least one echo time;
at least one processor; and
a memory, with computer code instructions stored thereon, the computer code instructions, when executed by the at least one processor, cause the at least one processor to;
generate an apparent longitudinal relaxation time (T1app) map, representing a spatial distribution of T1app within the anatomical region using the first MR dataset, the second MR dataset and a constant value for a transmit radio frequency (RF) field within the anatomical region;
estimate a first transmit RF field map by scaling the T1app map by a first constant value of longitudinal relaxation time (T1), the first constant value of T1 associated with a first tissue type within the anatomical region;
estimate a second transmit RF field map by scaling the T1app map by a second constant value of T1, the second constant value of T1 associated with a second tissue type within the anatomical region; and
generate a third transmit RF field map using the estimated first transmit RF field map and the estimated second transmit RF field map, the third transmit RF field map representing a spatial distribution of the transmit RF field within the anatomical region.
2 Assignments
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Accused Products
Abstract
Variable flip angle techniques with constraints for reconstructing MR images include a processor generating a T1app map representing a spatial distribution of T1app within an anatomical region using a first MR dataset corresponding to a first flip angle (FA) and a second MR dataset corresponding to a second FA. The processor can estimate a first and second transmit RF field maps by scaling the T1app map by a first constant value of T1 associated with a first tissue type and a second constant value of T1 associated with a second tissue type, respectively. The processor can generate a third transmit RF field map using the first and second transmit RF field maps, and use the third transmit RF field map to construct MR images of the anatomical region. Weighted subtraction images can be created with improved contrast-to-noise ratio compared to images of the first and second MR datasets.
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Citations
20 Claims
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1. A magnetic resonance imaging (MRI) system comprising:
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a MRI scanner configured to acquire a first magnetic resonance (MR) dataset corresponding to a first flip angle and a second MR dataset corresponding to a second flip angle by imaging an anatomical region using at least one echo time; at least one processor; and a memory, with computer code instructions stored thereon, the computer code instructions, when executed by the at least one processor, cause the at least one processor to; generate an apparent longitudinal relaxation time (T1app) map, representing a spatial distribution of T1app within the anatomical region using the first MR dataset, the second MR dataset and a constant value for a transmit radio frequency (RF) field within the anatomical region; estimate a first transmit RF field map by scaling the T1app map by a first constant value of longitudinal relaxation time (T1), the first constant value of T1 associated with a first tissue type within the anatomical region; estimate a second transmit RF field map by scaling the T1app map by a second constant value of T1, the second constant value of T1 associated with a second tissue type within the anatomical region; and generate a third transmit RF field map using the estimated first transmit RF field map and the estimated second transmit RF field map, the third transmit RF field map representing a spatial distribution of the transmit RF field within the anatomical region. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for magnetic resonance imaging (MRI), comprising:
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receiving, by at least one processor, a first magnetic resonance (MR) dataset corresponding to a first flip angle and a second MR dataset corresponding to a second flip angle, the first MR dataset and the second MR dataset acquired by imaging an anatomical region using at least one echo time; generating, by at least one processor, an apparent longitudinal relaxation time (T1app) map, representing a spatial distribution of T1app within the anatomical region using the first MR dataset, the second MR dataset and a constant value for a transmit radio frequency (RF) field within the anatomical region; estimating, by the at least one processor, a first transmit RF field map by scaling the T1app map by a first constant value of longitudinal relaxation time (T1), the first constant value of T1 associated with a first tissue type within the anatomical region; estimating, by the at least one processor, a second transmit RF field map by scaling the T1app map by a second constant value of T1, the second constant value of T1 associated with a second tissue type within the anatomical region; and generating, by the at least one processor, a third transmit RF field map using the estimated first transmit RF field map and the estimated second transmit RF field map, the third transmit RF field map representing a spatial distribution of the transmit RF field within the anatomical region. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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20. A non-transitory computer-readable medium comprising computer code instructions stored thereon, the computer code instructions when executed by a at least one processor cause the at least one processor to:
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receive a first magnetic resonance (MR) dataset corresponding to a first flip angle and a second MR dataset corresponding to a second flip angle, the first MR dataset and the second MR dataset acquired by imaging an anatomical region using at least one echo time; generate an apparent longitudinal relaxation time (T1app) map, representing a spatial distribution of T1app within the anatomical region using the first MR dataset, the second MR dataset and a constant value for a transmit radio frequency (RF) field within the anatomical region; estimate a first transmit RF field map by scaling the T1app map by a first constant value of longitudinal relaxation time (T1), the first constant value of T1 associated with a first tissue type within the anatomical region; estimate a second transmit RF field map by scaling the T1app map by a second constant value of T1, the second constant value of T1 associated with a second tissue type within the anatomical region; and generate a third transmit RF field map using the estimated first transmit RF field map and the estimated second transmit RF field map, the third transmit RF field map representing a spatial distribution of the transmit RF field within the anatomical region.
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Specification