MAGNETIC RESONANCE IMAGING APPARATUS

• US 20070088212A1
• Filed: 10/17/2006
• Published: 04/19/2007
• Est. Priority Date: 10/19/2005
• Status: Abandoned Application

• Current Assignee: GE Medical Systems Global Technology Company LLC (GE Healthcare Technologies, Inc.)
• Original Assignee: GE Yokogawa Medical Systems Limited (GE Aerospace)
• Inventors: Takei, Naoyuki, Tsukamoto, Tetsuji
• Application Number:
  US11/550,071
• Publication Number:
  US 20070088212A1
• Time in Patent Office: Days
• US Class Current: 600/413
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: A61B 5/7207 of noise induced by motion artifacts
• CPC Class Codes: G01R 33/563 of moving material, e.g. flow contrast angiography
• CPC Class Codes: G01R 33/5635 Angiography, e.g. contrast-enhanced angiography [CE-MRA] or time-of-flight angiography [TOF-MRA]
• CPC Class Codes: G01R 33/56509 due to motion, displacement or flow, e.g. gradient moment nulling G01R33/567 takes precedence
• CPC Class Codes: G01R 33/5673 Gating or triggering based on a physiological signal other than an MR signal, e.g. ECG gating or motion monitoring using optical systems for monitoring the motion of a fiducial marker
• CPC Class Codes: G01R 33/5676 Gating or triggering based on an MR signal, e.g. involving one or more navigator echoes for motion monitoring and correction

Abstract

For the purpose of improving contrast of an image, and hence, image quality, a navigator sequence NS for acquiring navigator echo data is performed before performing an imaging sequence IS each time, and a displacement N of the diaphragm caused by respiratory motion is detected based on the navigator echo data. Then, an imaging sequence IS for acquiring imaging data in the imaged region is performed if the detected displacement N caused by respiratory motion N of the subject falls within an acceptance window AW. Thereafter, each of a plurality of sets of imaging data acquired in the imaging sequence IS performed a plurality of number of times is corrected using a correction factor corresponding to a time interval between a first imaging sequence IS1 in which each set of imaging data is acquired and a second imaging sequence IS2 performed before the first imaging sequence IS1, and a slice image is produced from the plurality of corrected sets of imaging data.

Claims

1. A magnetic resonance imaging apparatus comprising:

a scanning device performing a plurality of number of times an imaging sequence for emitting an electromagnetic wave toward a subject to excite an imaged region in said subject in a static magnetic field space, and acquiring magnetic resonance signals generated in said imaged region in said subject as a set of imaging data; and

an image producing device for producing an image of said subject based on a plurality of said sets of imaging data acquired by said scanning device performing said imaging sequence, wherein;

said magnetic resonance imaging apparatus further comprises a body motion detecting device for periodically detecting a displacement caused by body motion of said subject;

said scanning device performs said imaging sequence if said displacement caused by body motion detected by said body motion detecting device falls within a specified range; and

said image producing device corrects each of said plurality of sets of imaging data acquired in said imaging sequence performed a plurality of number of times by said scanning device using a correction factor corresponding to a time interval between a first imaging sequence in which each set of said imaging data is acquired and a second imaging sequence performed before said first imaging sequence, and then produces an image of said subject based on said plurality of corrected sets of imaging data.

2. The magnetic resonance imaging apparatus of claim 1, wherein:

said body motion detecting device detects a displacement caused by respiratory motion of said subject.

3. The magnetic resonance imaging apparatus of claim 2, wherein:

said body motion detecting device detects said displacement caused by respiratory motion for each cardiac cycle of said subject.

4. The magnetic resonance imaging apparatus of claim 3, wherein:

said body motion detecting device repetitively detects said displacement caused by respiratory motion at the same phase over cardiac cycles of said subject; and

said scanning device performs said imaging sequence at the same phase over cardiac cycles of said subject.

5. The magnetic resonance imaging apparatus of claim 1, wherein:

said scanning device performs said imaging sequence on a region containing the coronary artery of said subject as said imaging region.

6. The magnetic resonance imaging apparatus of claim 1, wherein:

said scanning device performs a navigator sequence for acquiring said magnetic resonance signal as navigator echo data, before performing said imaging sequence; and

said body motion detecting device detects said displacement caused by body motion based on said navigator echo data acquired by said scanning device performing said navigator sequence.

7. The magnetic resonance imaging apparatus of claim 6, wherein:

said scanning device performs said navigator sequence to acquire said navigator echo data on a region containing the diaphragm in said subject.

8. The magnetic resonance imaging apparatus of claim 1, further comprising:

a display device for displaying on its display screen an image of said subject produced by said image producing device.