Abstract: In MRI using an SE-based pulse sequence, an object is to suppress flow artifacts and acquire a flow artifact-free image regardless a velocity or a direction of blood flow. A pair of gradient magnetic field pulses are applied before and after a 180-degree pulse of the SE-based pulse sequence, and a plurality of times of imaging are performed using varying intensities of the pair of gradient magnetic field pulses. Image reconstruction is performed by performing a Fourier transformation on measurement data obtained through the plurality of times of imaging in an axial direction of the intensities of the gradient magnetic field pulses, that is, a velocity encoding direction. As a result, images can be separated for each velocity of a stationary tissue and a non-stationary component included in tissues, and an image of spins with a velocity of zero, that is, a flow artifact-free image of the stationary tissue, can be obtained.

Abstract: Preventing blood flow artifacts from being increased in an imaging plane allows reduction of the blood flow artifacts in the cross section subsequently excited. In the imaging using a spin-echo (SE) pulse sequence, an excitation width of a 90° pulse is extended from an imaging plane to one side. This one side indicates a downstream side of the blood flow with respect to a vessel of interest. In imaging multiple slices, the order of measuring the multiple imaging slices is set along the direction in which the width is extended.

Abstract: For a complex image to be complexly added, appropriate phase correction is executed by a simple method to prevent occurrence of an artifact in a signal region and to reduce noise in a background region. Two or more types of smoothing processing with different smoothing degrees are executed on a phase image of the complex image to obtain two or more types of smoothed phase images having different smoothing degrees. A weight for each of these smoothed phase images is calculated based on a signal value (SNR) of an intensity image, and addition is performed by a weight for each signal value to obtain a smoothed phase image for correction. After a phase of the complex image is corrected using the smoothed phase image, a phase-corrected complex image is complexly added. As a result, phase correction equivalent to phase correction in which a smoothing degree is weakened in the signal region and a smoothing degree is strengthened in the background region is realized.

Abstract: Distortion generated in an image is effectively corrected in imaging using an EPI sequence such as DWI without extending an imaging time. After one excitation RF pulse of EPI is applied, a navigator scan in which the polarity of the phase encoding is opposite to that of the main scan is performed continuously to the main scan, and the distortion of the image by using the navigator scan data obtained by the navigator scan is corrected. In a case of multi-shot, phase information obtained from the navigator scan data for each shot is used to perform phase correction and multi-shot reconstruction on the main scan data of each shot.

Abstract: For a complex image to be complexly added, appropriate phase correction is executed by a simple method to prevent occurrence of an artifact in a signal region and to reduce noise in a background region. Two or more types of smoothing processing with different smoothing degrees are executed on a phase image of the complex image to obtain two or more types of smoothed phase images having different smoothing degrees. A weight for each of these smoothed phase images is calculated based on a signal value (SNR) of an intensity image, and addition is performed by a weight for each signal value to obtain a smoothed phase image for correction. After a phase of the complex image is corrected using the smoothed phase image, a phase-corrected complex image is complexly added. As a result, phase correction equivalent to phase correction in which a smoothing degree is weakened in the signal region and a smoothing degree is strengthened in the background region is realized.

Abstract: Distortion generated in an image is effectively corrected in imaging using an EPI sequence such as DWI without extending an imaging time. After one excitation RF pulse of EPI is applied, a navigator scan in which the polarity of the phase encoding is opposite to that of the main scan is performed continuously to the main scan, and the distortion of the image by using the navigator scan data obtained by the navigator scan is corrected. In a case of multi-shot, phase information obtained from the navigator scan data for each shot is used to perform phase correction and multi-shot reconstruction on the main scan data of each shot.