Magnetic resonance imaging apparatus, method for controlling the same, and control program of magnetic resonance imaging apparatus

A magnetic resonance imaging apparatus comprising:

• a static magnetic field generating device configured to apply a static magnetic field to an imaging region;
• an imaging unit including an RF signal irradiation device configured to irradiate a subject arranged in the imaging region with a high-frequency magnetic field pulse, and a gradient magnetic field generating device configured to generate a gradient magnetic field pulse, the imaging unit acquiring a nuclear magnetic resonance signal generated from the subject in response to the high-frequency magnetic field pulse and the gradient magnetic field pulse;
• a processing device coupled to the imaging unit, the processing device controlling the imaging unit to repeatedly execute the application of the high-frequency magnetic field pulse and the gradient magnetic field pulse and the acquisition of the nuclear magnetic resonance signal at predetermined timings in accordance with a predetermined imaging pulse sequence and controlling the imaging unit to acquire a necessary number of nuclear magnetic resonance signals for image reconstruction;
• and
• a camera configured to continuously and optically image the subject arranged in the imaging region during an operation of the imaging unit, wherein
• the processing device takes in images captured by the camera at a predetermined frame rate,
• the imaging pulse sequence is divided into small sequences at a time width corresponding to the frame rate, and
• the processing device controls the imaging unit to sequentially execute the small sequences by repeating an operation of:
• before controlling the imaging unit to execute one small sequence, detecting a displacement of the subject based on an image of the latest frame taken in at the frame rate, determining whether the detected displacement reaches a predetermined displacement caused by a predetermined cyclic motion of the subject, and controlling the imaging unit to execute the small sequence when the detected displacement reaches the predetermined displacement and waiting until an image of a next frame is taken in according to the frame rate without executing the small sequence when the detected displacement does not reach the predetermined displacement.

A magnetic resonance imaging apparatus comprising:

• a static magnetic field generating device configured to apply a static magnetic field to an imaging region;
• an imaging unit including an RF signal irradiation device configured to irradiate a subject arranged in the imaging region with a high-frequency magnetic field pulse, and a gradient magnetic field generating device configured to generate a gradient magnetic field pulse, the imaging unit acquiring a nuclear magnetic resonance signal generated from the subject in response to the high-frequency magnetic field pulse and the gradient magnetic field pulse;
• and
• a processing device coupled to the imaging unit, the processing device controlling the imaging unit to repeatedly execute the application of the high-frequency magnetic field pulse and the gradient magnetic field pulse and the acquisition of the nuclear magnetic resonance signal at predetermined timings in accordance with a predetermined imaging pulse sequence and controlling the imaging unit to acquire a necessary number of nuclear magnetic resonance signals for image reconstruction, wherein
• the processing device takes in images from a camera connected to the processing device at a predetermined frame rate,
• the imaging pulse sequence is divided into small sequences at a time width corresponding to the frame rate, and
• the processing device controls the imaging unit to sequentially execute the small sequences at a time interval corresponding to the frame rate by repeating an operation of:
• before controlling the imaging unit to execute one small sequence, detecting a displacement of the subject with respect to a predetermined reference position or a motion speed of the subject based on an image of a latest frame taken in at the frame rate, and controlling the imaging unit to execute the small sequence when a detection result is within a predetermined allowable range and waiting until an image of a next frame is taken in according to the frame rate without causing the imaging unit to execute the small sequence when the detection result exceeds the allowable range.

A method for controlling a magnetic resonance imaging apparatus which applies a high-frequency magnetic field pulse and a gradient magnetic field pulse to a subject arranged in an imaging region at a timing according to a predetermined imaging pulse sequence and acquires a nuclear magnetic resonance signal generated from the subject, the method comprising:

• taking in images from a camera connected to the magnetic resonance imaging apparatus at a predetermined frame rate;
• and
• causing the magnetic resonance imaging apparatus to sequentially execute small sequences, obtained by dividing the imaging pulse sequence so as to have a time width corresponding to the frame rate, at a time interval corresponding to the frame rate by repeating an operation of:
• detecting a displacement of the subject with respect to a predetermined reference position or a motion speed of the subject based on an image of the latest frame taken in at the frame rate, and
• causing the magnetic resonance imaging apparatus to execute the small sequences when a detection result is within a predetermined allowable range and waiting until an image of a next frame is taken in according to the frame rate without executing the small sequences when the detection result exceeds the allowable range.