Model-based reconstruction for looping-star pulse sequences in MRI
AssigneeThe Regents of the University of Michigan
InventorsHaowei Xiang, Jeffrey Allen Fessler, Douglas Clair Noll
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Abstract
The following relates generally to improved techniques for magnetic resonance imaging (MRI). In particular, the following relates to improving techniques of data acquisition and image reconstruction in relation to the “looping star” pulse sequence, which was developed to reduce acoustic noise. For example, techniques disclosed herein address the problem that looping star pulse sequence suffers from the overlapping echo effect. For instance, some implementations build echo-in and echo-out signal matrixes, and then sum the matrices to create a system matrix.
Claims22
A method for use in T*2 weighted magnetic resonance imaging (MRI) image reconstruction, the method comprising:
- collecting, via one or more processors, a plurality of echo signals, the plurality of echo signals being created by a MRI machine:
- (i) applying a gradient magnetic field to a subject, and (ii) applying a sequence of radio frequency (RF) pulses to the subject, wherein the plurality of echo signals include at least one overlap between echoes, and wherein the plurality of echo signals are collected in a phase during which the sequence of RF pulses are not being applied to the subject;
- building, via the one or more processors, an echo-in signal matrix based on k-space sampling locations;
- building, via the one or more processors, an echo-out signal matrix based on k-space sampling locations;
- summing, via the one or more processors, the echo-in signal matrix with the echo-out signal matrix to create a system matrix that models overlapping echoes;
- and
- reconstructing, via the one or more processors, a MRI image and/or rate map based on the system matrix, and the collected plurality of echo signals to resolve the overlapping echoes modeled in the system matrix.
A device for use in T*2 weighted magnetic resonance imaging (MRI) image reconstruction, the device comprising one or more processors configured to:
- collect a plurality of echo signals, the plurality echo signals being a plurality of signals that are created by a MRI machine:
- (i) applying a gradient magnetic field to a subject, and (ii) applying a sequence of radio frequency (RF) pulses to the subject, wherein the plurality of echo signals include at least one overlap between echoes, and wherein the one or more processors are further configured to collect in a phase during which the sequence of RF pulses are not being applied to the subject;
- build an echo-in signal matrix based on k-space sampling locations;
- build an echo-out signal matrix based on the k-space sampling locations;
- sum the echo-in signal matrix with the echo-out signal matrix to create a system matrix that models overlapping echoes;
- and
- reconstruct a MRI image and/or rate map based on the system matrix, and the collected plurality of echo signals to resolve the overlapping echoes modeled in the system matrix.
A magnetic resonance imaging (MRI) system for use in T*2 weighted MRI image reconstruction, the MRI system comprising:
- one or more processors;
- a gradient coil;
- at least one radio frequency (RF) transmit coil;
- at least one RF receive coil;
- and
- one or more memories coupled to the one or more processors;
- the one or more memories including computer executable instructions stored therein that, when executed by the one or more processors, cause the one or more processors to:
- collect a plurality of echo signals, the plurality of echo signals being a plurality of signals that are created by the MRI system:
- (i) applying a gradient magnetic field to a subject, and (ii) applying a sequence of RF pulses to the subject, wherein the plurality of echo signals include at least one overlap between echoes, and wherein the one or more memories including computer executable instructions stored therein that, when executed by the one or more processors, further cause the one or more processors to collect in a phase during which the sequence of RF pulses are not being applied to the subject;
- build an echo-in signal matrix based on k-space sampling locations;
- build an echo-out signal matrix based on the k-space sampling locations;
- sum the echo-in signal matrix with the echo-out signal matrix to create a system matrix that models overlapping echoes;
- and
- reconstruct a MRI image and/or rate map based on the system matrix, and the collected plurality of echo signals to resolve the overlapping echoes modeled in the system matrix.
Dependencies are inferred from the claim text.