Displacement imaging of spinal cord using q-space diffusion-weighted MRI

Displacement MR images of water in in vitro rat spinal cord were computed f rom q-space analysis of high b value diffusion-weighted MRI data. It is dem onstrated that q-space analysis of heavily diffusion-weighted MRI (qs-DWI) provides MR images in which physical parameters of the tissues such as the mean displacement and the probability for zero displacement of the water mo lecules are used as contrasts. It is shown that these MR images provide str uctural information surpassing the spatial resolution of conventional MRI b y several orders of magnitude. This imaging methodology was used to follow spinal cord maturation in the rat. It was found that changes in the diffusi on characteristics of white matter upon maturation are responsible for the emergence of gray/white matter contrast. The mean displacement of water mol ecules in the white and gray matter of the mature rat spinal cord was found to be 2-3, and 8-10 microns, respectively, The potential and the limitatio ns of this new imaging methodology for early detection of white matter diso rders are discussed. (C) 2000 Wiley-Liss, Inc.