OBJECTIVETo investigate the correlation between the diffusion anisotropy of the white matter fibers and the cognitive function in patients with leukoaraiosis (LA).

METHODSThirty-one LA patients were enrolled in this study, including 13 with grade LA-1 (mild), 12 with grade LA-2 (moderate) and 6 with grade LA-3 (severe) condition. The control group consisted of 18 subjects who were free of obvious clinical symptoms or had only mild dizziness and headache but with negative history for neural system diseases and in the absence of cognitive dysfunction, brain trauma, positive signs in neurological examinations, or abnormities in MRI examination. The Mini-mental State Examination (MMSE) was applied to evaluate the patients' cognitive function. The LA patients underwent examination with diffusion tensor MR imaging (DTI), and the FA and MD values in the normal-appearing white matter (NAWM) were measured.

RESULTSThe cognitive function of the LA patients tended to decline with the decrease of the MMSE scores, and their scores for time orientation, place orientation and calculation were significantly lower than those of the control group (P<0.05). No significant difference was found in memory, language and comprehensive abilities between the LA and control groups. In LA-1, LA-2 and total LA cases, the FA value in the NAWM was positively, and the MD value inversely, correlated to the cognitive function with correlation coefficients ranging from 0.5 to 0.8 (P<0.05).

CONCLUSIONThe DTI parameters of NAWM region are correlated to the cognitive function of LA patients. DTI is far more sensitive than MRI in evaluating cognitive dysfunction in LA patients.