Correction of motional artifacts in diffusion‐weighted images using a reference phase map

A method of correcting motional artifacts in diffusion‐weighted images is described. Motion causes changes in the phase of the k‐space NMR signal and thereby introduces positional shifts (or ghosts) in the spatial domain. By correcting the phase of the NMR signal before Fourier transformation, the image sharpness is greatly enhanced. The new method measures the phases of the NMR signal once and stores this phase information in a phase map. Subsequent images with motional artifacts are corrected during postprocessing using this reference phase map.

[1]  J. Kucharczyk,et al.  Early detection of regional cerebral ischemia in cats: Comparison of diffusion‐ and T2‐weighted MRI and spectroscopy , 1990, Magnetic resonance in medicine.

[2]  D Le Bihan,et al.  Measuring random microscopic motion of water in tissues with MR imaging: a cat brain study. , 1991, Journal of computer assisted tomography.

[3]  Wei Li,et al.  Fast magnetic resonance diffusion‐weighted imaging of acute human stroke , 1992, Neurology.

[4]  P. Grenier,et al.  MR imaging of intravoxel incoherent motions: application to diffusion and perfusion in neurologic disorders. , 1986, Radiology.

[5]  K Minematsu,et al.  Reversible Focal Ischemic Injury Demonstrated by Diffusion‐Weighted Magnetic Resonance Imaging in Rats , 1992, Stroke.

[6]  J. Frahm,et al.  Diffusion imaging of the human brain in vivo using high‐speed STEAM MRI , 1992, Magnetic resonance in medicine.

[7]  R. Turner,et al.  Echo‐planar imaging of diffusion and perfusion , 1991, Magnetic resonance in medicine.

[8]  R. Ordidge,et al.  Correction of motional artifacts in diffusion-weighted MR images using navigator echoes. , 1994, Magnetic resonance imaging.

[9]  J. Felmlee,et al.  Adaptive technique for high-definition MR imaging of moving structures. , 1989, Radiology.

[10]  P van Gelderen,et al.  Restricted and anisotropic displacement of water in healthy cat brain and in stroke studied by NMR diffusion imaging , 1991, Magnetic resonance in medicine.

[11]  J. E. Tanner,et al.  Spin diffusion measurements : spin echoes in the presence of a time-dependent field gradient , 1965 .