HIGH-RESOLUTION DIFFUSION-WEIGHTED MAGNETIC RESONANCE IMAGING

摘要

A system and method of obtaining diffusion weighted images uses a magnetic-resonance imaging system and includes, for at least a first slice, exciting spins of the slice, then: applying a diffusion weighting gradient in i'th direction of N diffusion- weighted directions; sweeping a readout gradient across an EPI short-axis blade oriented at a first angle, pulsing phase-encoding gradient, recording spin-echo signal magnitudes in k-space memory for the short-axis blade; and simultaneously rotating the diffusion gradient direction to a next direction of the N directions and rotating the short axis blade to another angle. Storing spin-echo signals in k-space memory is repeated for a rotated short-axis blade with the rotated diffusion gradient. Composite reconstruction is done by "training" the ith low-resolution image from Fourier transform of ith k-space blade with the ith high-resolution composite image from Fourier transform of collected k-space EPI blades of neighborhood diffusion directions.