Magnetic resonance imaging apparatus

Patent metadata

Field	Value
Publication number	US-10365344-B2
Application number	US-201514963973-A
Country	US
Kind code	B2
Filing date	Dec 9, 2015
Priority date	Jun 10, 2013
Publication date	Jul 30, 2019
Grant date	Jul 30, 2019

Abstract

An MRI system according to an embodiment includes an MRI sequence controller and an MRI system controller. Serving as a prescan unit, the MRI sequence controller performs a prescan for acquiring a sensitivity distribution of a coil. Serving as a main scan unit, the MRI sequence controller performs a main scan for acquiring signals of a magnetic resonance image. Serving as a corrector, the MRI system controller corrects the sensitivity distribution in accordance with a distortion that is contained in the magnetic resonance image and that results from the performing of the main scan. Serving as a generator, the MRI system controller generates an output magnetic resonance image using the corrected sensitivity distribution.

First claim

What is claimed is:

1. A magnetic resonance imaging (MRI) apparatus comprising:
MRI system components including a static field magnet and a gradient magnetic field coil, a radio frequency (RF) coil, RF transmitter and receiver circuits and at least one programmed computer connected to control said MRI system components so as to
perform a prescan acquiring signals from said RF coil which provide a sensitivity distribution of said RF coil;
perform a main scan acquiring signals from said RF coil which provides a magnetic resonance image;
correct the sensitivity distribution in accordance with a distortion contained in the magnetic resonance image and that results from performing the main scan; and
generate an output magnetic resonance image, using the corrected sensitivity distribution.

2. The magnetic resonance imaging apparatus according to claim 1 , wherein the distortion is a distortion that occurs along a phase-encoding direction in a k-space and that appears in the magnetic resonance image.

3. The magnetic resonance imaging apparatus according to claim 1 , wherein the sensitivity distribution is corrected by enhancing or reducing the sensitivity distribution in a direction determined in accordance with a direction of the distortion contained in the magnetic resonance image.

4. The magnetic resonance imaging apparatus according to claim 1 , wherein the sensitivity distribution is corrected by enhancing or reducing the sensitivity distribution using replication.

5. The magnetic resonance imaging apparatus according to claim 4 , wherein, for the replication, a point inside an edge corresponding to an object in the sensitivity distribution in a phase-encoding direction is replicated.

6. The magnetic resonance imaging apparatus according to claim 1 , wherein
for the prescan, sensitivity distributions of a plurality of RF coils are acquired, respectively,
parallel imaging is performed as the main scan,
an intermediate magnetic resonance image is generated by performing first unfolding processing on signals obtained by the parallel imaging and a mask or weighting information is generated using the generated intermediate magnetic resonance image, and
the output magnetic resonance image is generated by performing second unfolding processing using the sensitivity distribution of each RF coil obtained by the prescan, the signals obtained by the parallel imaging, and the mask or the weighting information.

7. The magnetic resonance imaging apparatus according to claim 1 , wherein EPI (Echo Planar Imaging) is performed as the main scan.

8. A magnetic resonance imaging (MRI) apparatus comprising:
MRI system components including a static field magnet and a gradient magnetic field coil, a plurality of radio frequency (RF) coils, RF transmitter and receiver circuits and at least one programmed computer connected to control said MRI system components so as to
perform a prescan acquiring sensitivity distributions of the plurality of radio frequency (RF) coils, respectively;
perform parallel imaging as a main scan for acquiring signals of a magnetic resonance image;
generate an intermediate magnetic resonance image by performing first unfolding processing on signals obtained by the parallel imaging and generate a mask or weighting information using the generated intermediate magnetic resonance image; and
generate an output magnetic resonance image by performing second unfolding processing using (a) the sensitivity distributions of the respective RF coils obtained by the prescan, (b) the signals obtained by the parallel imaging, and (c) the mask or the weighting information.

Assignees

• Toshiba Medical Sys Corp

Inventors

• Dannels Wayne R
• Shigeta Takashi

Classifications

• G01R33/56554 Primary

  caused by acquiring plural, differently encoded echo signals after one RF excitation, e.g. correction for readout gradients of alternating polarity in EPI · CPC title

• G01R33/5611

  Parallel magnetic resonance imaging, e.g. sensitivity encoding [SENSE], simultaneous acquisition of spatial harmonics [SMASH], unaliasing by Fourier encoding of the overlaps using the temporal dimension [UNFOLD], k-t-broad-use linear acquisition speed-up technique [k-t-BLAST], k-t-SENSE (structural details of arrays of sub-coils G01R33/3415) · CPC title

• A61B5/055 Primary

  involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging · CPC title

• G01R33/385

  using gradient magnetic field coils · CPC title

• G01R33/34

  Constructional details, e.g. resonators {, specially adapted to MR} · CPC title