Abstract: A magnetic resonance method and system are provided for generating real-time motion-corrected perfusion images based on pulsed arterial spin labeling (PASL) with a readout sequence such as a 3D gradient and spin echo (GRASE) image data acquisition block. The real-time motion correction is achieved by using a volumetric 3D EPI navigator that is provided during an intrinsic delay in the PASL sequence, which corrects for motion prospectively and does not extend the image data acquisition time as compared to a similar non-motion-corrected imaging procedure.

Abstract: A method for correcting for main magnetic field (B0) inhomogeneity in a Magnetic Resonance Imaging (MRI) scanner is disclosed. The method includes applying a first and a second three-dimensional volumetric navigator after an acquisition of a volume in a scanning sequence and before the next volume is acquired. From a resultant pair of navigator images, a magnetic field map is obtained by complex division of the pair of navigator images, and the field map is used to determine parameters to adjust the MRI scanner to compensate for B0 inhomogeneity. The navigators may excite only a portion of an entire object to be imaged, so that adjustment of the MR scanner can be done slice-by-slice or slab-by-slab. Motion correction can also be implemented by comparing the first navigator to a stored reference image and updating for motion before acquisition of the next volume in the scanning sequence.

Abstract: A method for MRI inter-scan motion correction includes performing (i) an anatomical localizer scan of a region of interest (ROI) to identify anatomical landmarks defining orientation of a surrounding field-of-view (FOV); (ii) an inter-scan motion reference scan of the ROI to acquire a reference inter-scan dataset indicating a reference navigator location in the ROI; and (iii) scans of the ROI to acquire k-space data. Prior to one or more of the scans, a motion correction process is performed that includes (a) performing an inter-scan motion tracking scan to acquire a tracking inter-scan dataset indicating an updated reference navigator location; (b) determining an estimation of inter-scan patient motion based on a comparison between the reference inter-scan and tracking inter-scan datasets; and (c) updating the FOV relative to the landmarks based on that estimation. Images of the ROI may be generated using the k-space data acquired with each of the scans.

Abstract: A system determines motion correction data for use in diffusion MR imaging using an RF signal generator and magnetic field gradient generator which sequentially acquire in a single first direction through a volume, first and second slice sets individually comprising multiple individual diffusion image slices. The first set of slices and the second set of slices are spatially interleaved within the volume, by providing in acquiring the second slice set, a low flip angle RF pulse successively followed by a non-diffusion image data readout magnetic field gradient for acquisition of data representing a two dimensional (2D) non-diffusion image used for motion detection of the first slice set successively followed by, a first diffusion imaging RF pulse followed by a first diffusion imaging phase encoding magnetic field gradient for preparation for acquiring data representing a diffusion image slice of the second slice set.

Abstract: In a magnetic resonance (MR) imaging method and apparatus, multiple diagnostic scans are obtained of an examination subject during an imaging session. An initial reference scan of the subject is obtained at the beginning of the session and, as the session proceeds, an automatic determination is made before each diagnostic scan is obtained as to whether the immediately preceding reference scan is still valid, primarily be checking whether an amount of patient movement has occurred that renders the immediately preceding reference scan invalid. Either a new reference scan is obtained before the next diagnostic scan, or, if still valid, the immediately preceding reference scan is used for the next diagnostic scan.

Abstract: A magnetic resonance (MR) method and system are provided for generating real-time prospective motion-corrected images using fast navigators. The real-time motion correction is achieved by using a 2D EPI navigator that is obtained using a simultaneous multi-slice blipped-CAIPI technique. The navigator parameters such as field of view, voxel size, and matrix size can be selected to facilitate fast acquisition while providing information sufficient to detect rotational motions on the order of several degrees or more and translational motions on the order of several millimeters or more. The total time interval for obtaining and reconstructing navigator data, registering the navigator image, and providing feedback to correct for detected motion, can be on the order of about 100 ms or less. This prospective motion correction can be used with a wide range of MR imaging techniques where the pulse sequences do not have significant intervals of “dead” time.

Abstract: A method for correcting for main magnetic field (B0) inhomogeneity in a Magnetic Resonance Imaging (MRI) scanner is disclosed. The method includes applying a first and a second three-dimensional volumetric navigator after an acquisition of a volume in a scanning sequence and before the next volume is acquired. From a resultant pair of navigator images, a magnetic field map is obtained by complex division of the pair of navigator images, and the field map is used to determine parameters to adjust the MRI scanner to compensate for B0 inhomogeneity. The navigators may excite only a portion of an entire object to be imaged, so that adjustment of the MR scanner can be done slice-by-slice or slab-by-slab. Motion correction can also be implemented by comparing the first navigator to a stored reference image and updating for motion before acquisition of the next volume in the scanning sequence.

Abstract: In a magnetic resonance (MR) imaging method and apparatus, multiple diagnostic scans are obtained of an examination subject during an imaging session. An initial reference scan of the subject is obtained at the beginning of the session and, as the session proceeds, an automatic determination is made before each diagnostic scan is obtained as to whether the immediately preceding reference scan is still valid, primarily be checking whether an amount of patient movement has occurred that renders the immediately preceding reference scan invalid. Either a new reference scan is obtained before the next diagnostic scan, or, if still valid, the immediately preceding reference scan is used for the next diagnostic scan.

Abstract: A magnetic resonance method and system are provided for generating real-time motion-corrected perfusion images based on pulsed arterial spin labeling (PASL) with a readout sequence such as a 3D gradient and spin echo (GRASE) image data acquisition block. The real-time motion correction is achieved by using a volumetric 3D EPI navigator that is provided during an intrinsic delay in the PASL sequence, which corrects for motion prospectively and does not extend the image data acquisition time as compared to a similar non-motion-corrected imaging procedure.

Abstract: A system determines motion correction data for use in diffusion MR imaging using an RF signal generator and magnetic field gradient generator which sequentially acquire in a single first direction through a volume, first and second slice sets individually comprising multiple individual diffusion image slices. The first set of slices and the second set of slices are spatially interleaved within the volume, by providing in acquiring the second slice set, a low flip angle RF pulse successively followed by a non-diffusion image data readout magnetic field gradient for acquisition of data representing a two dimensional (2D) non-diffusion image used for motion detection of the first slice set successively followed by, a first diffusion imaging RF pulse followed by a first diffusion imaging phase encoding magnetic field gradient for preparation for acquiring data representing a diffusion image slice of the second slice set.