Mri apparatus and a method of reducing imaging time

Patent metadata

Field	Value
Publication number	US-2016274207-A1
Application number	US-201615065397-A
Country	US
Kind code	A1
Filing date	Mar 9, 2016
Priority date	Mar 16, 2015
Publication date	Sep 22, 2016
Grant date	—

Abstract

In one embodiment, an MRI apparatus, includes a static magnetic field magnet configured to generate a static magnetic field, a gradient coil configured to generate a gradient magnetic field, a transmission and reception coil configured to transmit an RF signal and receive a magnetic resonance signal, and processing circuitry. The processing circuitry determines whether or not a prescan for calculating a correction value that corrects a phase error is skippable or reducible based on an imaging condition of a main scan, and executes a scan including at least the main scan in accordance with a result of the determination.

First claim

What is claimed is:

1 . An MRI apparatus, comprising:
a static magnetic field magnet configured to generate a static magnetic field; a gradient coil configured to generate a gradient magnetic field; a transmission and reception coil configured to transmit an RF signal and receive a magnetic resonance signal; and processing circuitry, wherein the processing circuitry determines whether or not a prescan for calculating a correction value that corrects a phase error is skippable or reducible based on an imaging condition of a main scan, and executes a scan including at least the main scan in accordance with a result of the determination.

2 . The MRI apparatus according to claim 1 , wherein
the processing circuitry determines whether the prescan is skippable or reducible, in accordance with similarity between the imaging condition of the main scan and a specified imaging condition.

3 . The MRI apparatus according to claim 2 , wherein
the processing circuitry determines whether the prescan is skippable or reducible in accordance with at least one similarity, out of similarity in offset amount from a magnetic field center, similarity in a parameter relating to resolution, and similarity relating to a prepulse, as the similarity.

4 . The MRI apparatus according to claim 1 , comprising
a storage circuitry configured to store a correction value corresponding to a specified imaging condition, wherein the processing circuitry uses the imaging condition of the main scan to refer to the correction value corresponding to the imaging condition in the storage circuitry and determines whether the prescan is skippable in accordance with a size of the correction value.

5 . An MRI apparatus, comprising:
a static magnetic field magnet configured to generate a static magnetic field; a gradient coil configured to generate a gradient magnetic field; a transmission and reception coil configured to transmit an RF signal and receive a magnetic resonance signal; processing circuitry; and memory circuitry, wherein the memory circuitry stores, for each type of correction value that corrects the phase error, a correction value determination result that is a result of determining whether the correction value is larger or smaller than a specified threshold, and the processing circuitry determines whether the prescan is skippable or reducible based on the correction value determination result.

6 . The MRI apparatus according to claim 5 , wherein
the processing circuitry determines whether the prescan is skippable or reducible in accordance with similarity between an imaging condition of a main scan and a specified imaging condition.

7 . The MRI apparatus according to claim 6 , wherein
the processing circuitry determines whether the prescan is skippable or reducible in accordance with at least one similarity, out of similarity in offset amount from a magnetic field center, similarity in a parameter relating to resolution, and similarity relating to a prepulse, as the similarity.

8 . The MRI apparatus according to claim 5 , wherein
the memory circuitry stores a changed imaging condition that is changed based on the correction value, together with the correction value determination result, and the processing circuitry determines whether the prescan is skippable or reducible based on the correction value determination result corresponding to the changed imaging condition, when executing a scan including at least the main scan in the changed imaging condition.

9 . The MRI apparatus according to claim 1 , wherein
the processing circuitry: (a) when the prescan is skipped, executes the scan corrected with all the correction values acquired before the prescan; and (b) when the prescan is reduced, executes the scan corrected with the correction values acquired in the reduced prescan and with part of the correction values acquired the before the prescan.

10 . The MRI apparatus according to claim 5 , wherein
the processing circuitry: (a) when the prescan is skipped, executes the scan corrected with all the correction values acquired before the prescan; and (b) when the prescan is reduced, executes the scan corrected with the correction values acquired in the reduced prescan and with part of the correction values acquired the before the prescan.

11 . The MRI apparatus according to claim 1 , wherein
the types of correction value include: (a) a correction value that corrects a zero-order phase error in a readout direction; (b) a correction value that corrects a first-order phase error in a slice direction; and (c) a correction value that corrects a first-order phase error component in the readout direction.

12 . The MRI apparatus according to claim 5 , wherein
the types of correction value include: (a) a correction value that corrects a zero-order phase error in a readout direction; (b) a correction value that corrects a first-order phase error in a slice direction; and (c) a correction value that corrects a first-order phase error component in the readout direction.

13 . The MRI apparatus according to claim 1 , wherein
the processing circuitry executes the scan with a reduced number of slices, when the prescan is reduced.

14 . The MRI apparatus according to claim 5 , wherein
the processing circuitry executes the scan with a reduced number of slices, when the prescan is reduced.

15 . A method of reducing imaging time, comprising:
determining whether a prescan for calculating a correction value that corrects a phase error is skippable or reducible based on an imaging condition of a main scan; and executing a scan including at least the main scan in accordance with a result of the determination.

Assignees

• Toshiba Kk
• Toshiba Medical Sys Corp

Inventors

• Kondo Hiroki
• Ozawa Shinya
• Umeda Masaaki
• Kassai Yoshimori
• Takabayashi Naoyuki

Classifications

• G01R33/56581 Primary

  due to Maxwell fields, i.e. concomitant fields · CPC title

• G01R33/56518

  due to eddy currents, e.g. caused by switching of the gradient magnetic field · CPC title

• G01R33/5616

  using gradient refocusing, e.g. EPI · CPC title

• G01R33/5617

  using RF refocusing, e.g. RARE · CPC title

• G01R33/34

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