MAGNETIC RESONANCE IMAGING APPARATUS AND CONTROLLING METHOD THEREOF

• US 20110038520A1
• Filed: 08/11/2010
• Published: 02/17/2011
• Est. Priority Date: 08/11/2009
• Status: Active Grant

• Current Assignee: Toshiba Medical Systems Corporation (Canon Inc.)
• Original Assignee: Toshiba Medical Systems Corporation (Canon Inc.)
• Inventors: YUI, Masao
• Granted Patent: US 9,696,401 B2
• Time in Patent Office: Days
• US Class Current: 382/131
• CPC Class Codes: G01R 33/4835 of multiple slices
• 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

In a magnetic resonance imaging apparatus according to the present embodiment, the sequence execution control unit alternately executes an imaging sequence of collecting data for generating a diagnostic image and a navigator sequence of collecting data for generating a navigator image that is an image for motion detection. The slice position detecting unit analyzes the navigator image generated from the data collected in the navigator sequence each time the navigator sequence is executed, and thereby detects the position of a mark indicating a slice excited by the imaging sequence executed prior to the navigator sequence. The respiratory motion estimating unit estimates the motion of a portion due to the subject'"'"'s respiration, based on the detected position of the mark.

Claims

1. A magnetic resonance imaging apparatus, comprising:

a sequence execution control unit configured to alternately execute an imaging sequence of collecting data for generating a diagnostic image and a navigator sequence of collecting data for generating a navigator image, the navigator image being an image for motion detection;

a slice position detecting unit configured to, each time the sequence execution control unit executes the navigator sequence, analyze the navigator image generated from the data collected in the navigator sequence, and thereby detect a position of a mark that indicates a slice excited by the imaging sequence executed prior to the navigator sequence;

a respiratory motion estimating unit configured to estimate motion of an portion due to respiration of a subject, based on the position of the mark detected by the slice position detecting unit; and

a sequence correcting unit configured to correct an imaging sequence to be subsequently executed, based on the motion of the portion estimated by the respiratory motion estimating unit.

2. The magnetic resonance imaging apparatus according to claim 1, wherein the slice position detecting unit detects, as the position of the mark, a position of a low-signal region formed on the navigator image by excitation of the slice in the imaging sequence.

3. The magnetic resonance imaging apparatus according to claim 1, wherein:

the navigator sequence is used to collect data from a dummy slice that is set in a different position from that of the slice of the diagnostic image; and

the slice position detecting unit detects, as the position of the mark, a high-signal region formed on the navigator image by excitation of the dummy slice in the imaging sequence.

4. The magnetic resonance imaging apparatus according to claim 1, wherein the slice position detecting unit performs model fitting onto a profile of the navigator image in a predetermined direction, and thereby detects the position of the mark.

5. The magnetic resonance imaging apparatus according to claim 2, wherein the slice position detecting unit performs model fitting onto a profile of the navigator image in a predetermined direction, and thereby detects the position of the mark.

6. The magnetic resonance imaging apparatus according to claim 3, wherein the slice position detecting unit performs model fitting onto a profile of the navigator image in a predetermined direction, and thereby detects the position of the mark.

7. The magnetic resonance imaging apparatus according to claim 1, wherein the slice position detecting unit performs pixel difference processing onto pixels aligned in a predetermined direction on the navigator image, and thereby detects the position of the mark.

8. The magnetic resonance imaging apparatus according to claim 2, wherein the slice position detecting unit performs pixel difference processing onto pixels aligned in a predetermined direction on the navigator image, and thereby detects the position of the mark.

9. The magnetic resonance imaging apparatus according to claim 3, wherein the slice position detecting unit performs pixel difference processing onto pixels aligned in a predetermined direction on the navigator image, and thereby detects the position of the mark.

10. A magnetic resonance imaging apparatus, comprising:

a sequence execution control unit configured to alternately execute an imaging sequence of collecting data for generating a diagnostic image and a navigator sequence of collecting data for generating a navigator image, the navigator mage being an image for motion detection;

a slice position detecting unit configured to, each time the sequence execution control unit executes the navigator sequence, analyze the navigator image generated from the data collected in the navigator sequence, and thereby detect a position of a mark that indicates a slice excited by the imaging sequence executed prior to the navigator sequence; and

a respiratory motion estimating unit configured to estimates motion of a portion due to respiration of a subject, based on the position of the mark detected by the slice position detecting unit.

11. A method of controlling a magnetic resonance imaging apparatus, comprising:

controlling a sequence execution control unit to alternately execute an imaging sequence of collecting data for generating a diagnostic image and a navigator sequence of collecting data for generating a navigator image, the navigator image being an image for motion detection;

controlling a slice position detecting unit to analyze the navigator image generated from the data collected in the navigator sequence each time the sequence execution control unit executes the navigator sequence, and thereby detect a position of a mark that indicates a slice excited by the imaging sequence executed prior to the navigator sequence; and

controlling a respiratory motion estimating unit to estimate motion of a portion due to respiration of a subject based on the position of the mark detected by the slice position detecting unit.