Anisotropy of water diffusion in corona radiata and cerebral peduncle in patients with hemiparesis

Diffusion tensor imaging is a magnetic resonance method which provides quan titative measurements of the directionality (anisotropy) of diffusion. Anis otropy measurements can be used to obtain quantitative information about th e microstructural integrity of white matter tracts. In intact tracts diffus ion is restricted and directional because water molecules move predominantl y longitudinally to tracts. The aim of this study was to measure the anisot ropy of diffusion in patients with chronic hemiparesis. We measured in the corona radiata and the cerebral peduncle in 10 patients with a chronic hemi paresis and supratentorial lesions and 10 control subjects in regions of in terest. In all patients anisotropy was reduced in the coronal radiata contr alateral to the hemiparesis by more than 3 SD compared to control subjects. In three patients, each of which had a severe hemiparesis, anisotropy in t he cerebral peduncle was reduced by more than 3 SD compared to normal contr ol subjects. Our findings suggest that reduced anisotropy is associated wit h chronic hemiparesis. (C) 1999 Academic Press.