Magnetic resonance imaging apparatus and program

Patent metadata

Field	Value
Publication number	US-2019107595-A1
Application number	US-201716086766-A
Country	US
Kind code	A1
Filing date	Mar 31, 2017
Priority date	Mar 31, 2016
Publication date	Apr 11, 2019
Grant date	—

Abstract

An MRI apparatus comprising a signal analyzing unit for determining a feature quantity of a navigator signal, and obtaining data representing a temporal change of the feature quantity for each coil element; a transforming unit for transforming the data obtained for each coil element into frequency spectra FS1 to FS16; and a selecting unit for selecting a coil element for determining a signal value of a body-motion signal for the subject from among coil elements E1 to E16 based on the frequency spectra FS1 to FS16.

First claim

1 . A magnetic resonance imaging apparatus comprising:
a scanning section for performing a first sequence a plurality of number of times, said first sequence being for generating a first MR signal containing information on body motion from a moving body part in a subject; a coil apparatus having a plurality of coil elements for receiving said first MR signal; a signal analyzing unit for obtaining data, said signal analyzing unit determining a feature quantity of a navigator signal containing information on said first MR signal received by each of said plurality of coil elements, and obtaining data representing a temporal change of said feature quantity for each said coil element; a transforming unit for transforming said data obtained for each said coil element into a frequency spectrum; and a selecting unit for selecting a coil element for determining a signal value of a body-motion signal for said subject from among said plurality of coil elements based on said frequency spectrum.

2 . The magnetic resonance imaging apparatus as recited in claim 1 , wherein said selecting unit detects a first peak reflecting motion of said moving body part and a second peak reflecting motion of said moving body part from among a plurality of peaks contained in said frequency spectrum to select said coil element based on one of peak values of said first and second peaks.

3 . The magnetic resonance imaging apparatus as recited in claim 2 , wherein said selecting unit detects a third peak not reflecting motion of said moving body part from among the plurality of peaks contained in said frequency spectrum to select said coil element based on a peak value of said third peak and said one of peak values.

4 . The magnetic resonance imaging apparatus as recited in claim 3 , wherein said selecting unit determines a ratio between said one of peak values and the peak value of said third peak for each said coil element to select said coil element based on said ratio.

5 . The magnetic resonance imaging apparatus as recited in claim 4 , wherein said scanning section performs a first scan for selecting a coil element, and said first sequence is performed a plurality of number of times in said first scan.

6 . The magnetic resonance imaging apparatus as recited in claim 5 , further comprising:
a producing unit for producing a profile representing a change of signal intensity for said moving body part in a specified direction based on a navigator signal containing information on said first MR signal received by the coil element selected by said selecting unit; and a determining unit for determining, based on said profile, a signal value of the body-motion signal when said first scan is being performed.

7 . The magnetic resonance imaging apparatus as recited in claim 5 , wherein:
said scanning section performs a second scan for determining a respiration signal for the subject, and in said second scan, a second sequence is performed a plurality of number of times, said second sequence being for generating a second MR signal containing information on body motion from said moving body part in said subject.

8 . The magnetic resonance imaging apparatus as recited in claim 7 , further comprising:
a producing unit for producing a profile representing a change of signal intensity for said moving body part in a specified direction based on a navigator signal containing information on said second MR signal received by the coil element selected by said selecting unit; and a determining unit for determining, based on said profile, a signal value of the body-motion signal when said second scan is being performed.

9 . The magnetic resonance imaging apparatus as recited in claim 6 , wherein:
said selecting unit selects two or more coil elements from among said plurality of coil elements, said producing unit produces two or more profiles corresponding to the two or more selected coil elements, and said unit for determining a body-motion signal determines a combined profile by combining said two or more profiles together, and determines a signal value of said body-motion signal based on said combined profile.

10 . The magnetic resonance imaging apparatus as recited in claim 9 , wherein said unit for determining a body-motion signal applies weighting to each of said two or more profiles with said ratio determined for each of said two or more coil elements, and determines said combined profile by adding said two or more weighted profiles together.

11 . The magnetic resonance imaging apparatus as recited in claim 6 , wherein:
said scanning section performs a third scan for acquiring an image of a body part to be imaged in the subject, and in said third scan, a third sequence for generating a third MR signal containing information on body motion from said moving body part in said subject, and a fourth sequence for generating a fourth MR signal containing image information for said subject are performed.

12 . The magnetic resonance imaging apparatus as recited in claim 11 , comprising a defining unit for defining, based on said body-motion signal, a window for deciding whether to perform said fourth sequence or not.

13 . The magnetic resonance imaging apparatus as recited in claim 1 , wherein said first sequence has a readout gradient pulse applied after an RF pulse.

14 . The magnetic resonance imaging apparatus as recited in claim 1 , wherein said feature quantity is a peak value of said navigator signal, a signal value of said navigator signal at a center of k-space, or an area of said navigator signal.

15 . The magnetic resonance imaging apparatus as recited in claim 1 , wherein said body-motion signal is a respiration signal.

16 . A method for a magnetic resonance imaging (MRI) apparatus, the MRI apparatus comprising a plurality of coil elements for receiving MR signals, the method comprising:
performing a first sequence a plurality of number of times, said first sequence being for generating a first MR signal containing information on body motion from a moving body part in a subject; determining a feature quantity of a navigator signal containing information on said first MR signal received by each of said plurality of coil elements; obtaining data representing a temporal change of said feature quantity for each said coil element; transforming said data obtained for each said coil element into a frequency spectrum; and selecting a coil element for determining a signal value of a body-motion signal for said subject from among said plurality of coil elements based on said frequency spectrum.

17 . The method of claim 16 , wherein selecting the coil element comprises:
detecting a first peak reflecting motion of said moving body part and a second peak reflecting motion of said moving body part from among a plurality of peaks contained in said frequency spectrum to select said coil element based on one of peak values of said first and second peaks.

18 . The method of claim 16 , further comprising:
producing a profile representing a change of signal intensity for said moving body part in a specified direction based on the navigator signal containing information on said first MR signal received by the selected coil element; and determining, based on said profile, a signal value of the body-motion signal when said first scan is being performed.

19 . The method of claim 16 , further comprising:
selecting two or more coil elements from among said plurality of coil elements; producing two or more profiles corresponding to the two or more selected c

Assignees

• Gen Electric

Inventors

• Iwadate Yuji

Classifications

• G01R33/3415

  comprising arrays of sub-coils {, i.e. phased-array coils with flexible receiver channels} · CPC title

• G01R33/5676

  Gating or triggering based on an MR signal, e.g. involving one or more navigator echoes for motion monitoring and correction · CPC title

• G01R33/56509 Primary

  due to motion, displacement or flow, e.g. gradient moment nulling (G01R33/567 takes precedence) · CPC title