Magnetic resonance imaging apparatus and method controlling execution of a pulse sequence based on recovery of longitudinal magnetization of a monitor region

• US 10,386,442 B2
• Filed: 06/09/2016
• Issued: 08/20/2019
• Est. Priority Date: 10/05/2015
• Status: Active Grant

• Current Assignee: Canon Medical Systems Corporation (Canon Inc.)
• Original Assignee: Canon Medical Systems Corporation (Canon Inc.)
• Inventors: Bannae, Shuhei
• Primary Examiner(s): Tang, Minh N
• Application Number:
  US15/177,432
• Publication Number:
  US 20170097401A1
• Time in Patent Office: 1,167 Days
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: A61B 5/33 specially adapted for cooperation with other devices
• CPC Class Codes: A61B 5/704 Tables
• CPC Class Codes: A61B 5/7285 for synchronising or triggering a physiological measurement or image acquisition with a physiological event or waveform, e.g. an ECG signal A61B6/5205, A61B6/541, A61B8/5207, A61B8/543 take precedence
• CPC Class Codes: G01R 33/543 Control of the operation of the MR system, e.g. setting of acquisition parameters prior to or during MR data acquisition, dynamic shimming, use of one or more scout images for scan plane prescription G01R33/546 takes precedence
• CPC Class Codes: G01R 33/5602 by filtering or weighting based on different relaxation times within the sample, e.g. T1 weighting using an inversion pulse
• 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

Abstract

A Magnetic Resonance Imaging apparatus according to an embodiment includes processing circuitry. The processing circuitry is configured to execute a pulse sequence to acquire data from an image taking region after applying a pre-pulse in synchronization with a predetermined electrocardiographic waveform of the subject. The processing circuitry is configured to monitor recovery of longitudinal magnetization by acquiring data from a monitor region that is different from the image taking region, by using timing linked with the timing with which the pre-pulse is applied. The processing circuitry is configured to control execution of the pulse sequence on the basis of a signal value of the data from the monitor region.

Claims

1. A magnetic resonance imaging apparatus comprising:

processing circuitry configured to execute a pulse sequence to acquire data from an image taking region after applying a first pre-pulse to the image taking region in synchronization with a predetermined electrocardiographic waveform of a subject, wherein

the processing circuitry is further configured to;

acquire data from a monitor region that is different from the image taking region after applying a second pre-pulse to the monitor region, by using timing linked with timing with which the first pre-pulse is applied;

monitor a degree of recovery of longitudinal magnetization in the data acquired from the monitor region; and

control execution of the pulse sequence in accordance with the degree of recovery of longitudinal magnetization.

2. The magnetic resonance imaging apparatus according to claim 1, wherein the monitor region is set so as to include a tissue of which a longitudinal relaxation time period is equal to or longer than a longitudinal relaxation time period of a tissue of which a signal value is suppressed by the first pre-pulse.

3. The magnetic resonance imaging apparatus according to claim 1, wherein the processing circuitry exercises control so that, when a signal value of the longitudinal magnetization is equal to or larger than a predetermined threshold value, the pulse sequence is executed with an upcoming predetermined electrocardiographic waveform and exercises control so that, when the signal value of the longitudinal magnetization is smaller than the predetermined threshold value, the pulse sequence is not executed with the upcoming predetermined electrocardiographic waveform.

4. The magnetic resonance imaging apparatus according to claim 1, wherein the processing circuitry further receives, from an operator, an operation to designate a range within an image of the subject being displayed on a display and sets the monitor region on a basis of the designated range.

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

the processing circuitry is configured to:

acquire data from the monitor region every time the predetermined electrocardiographic waveform occurs, and

every time data is acquired from the monitor region, obtain a signal value of the acquired data.

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

the processing circuitry is configured to:

acquire the data from the monitor region by using tuning excluding a time period during which the data is acquired from the image taking region, and

every time data is acquired from the monitor region, obtain a signal value of the acquired data.

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

the processing circuitry is configured to set a time period from a time when the predetermined electrocardiographic waveform is detected to a time when the first pre-pulse is applied, in accordance with how large a difference is between the signal value and the predetermined threshold value.

8. The magnetic resonance imaging apparatus according to claim 1, wherein the image taking region is set so as to include a myocardium of the subject.

9. The magnetic resonance imaging apparatus according to claim 1, wherein the monitor region is set so as to include cerebrospinal fluid of the subject.

10. The magnetic resonance imaging apparatus according to claim 1, wherein the first pre-pulse is a pre-pulse configured to change longitudinal magnetization of a nuclear spin into a negative value.

11. A magnetic resonance imaging method comprising:

executing a pulse sequence to acquire data from an image taking region after applying a first pre-pulse to the image taking region in synchronization with a predetermined electrocardiographic waveform of a subject wherein

the executing of the pulse sequence includes;

acquiring data from a monitor region that is different from the image taking region after applying a second pre-pulse to the monitor region, by using timing linked with timing with which the first pre-pulse is applied;

monitoring a degree of recovery of longitudinal magnetization in the data acquired from the monitor region; and

controlling execution of the pulse sequence in accordance with the degree of recovery of longitudinal magnetization.