[Distribution of ischemic leukoaraiosis in MRI: a difference from white matter lesions in CADASIL]

Previously, the distribution of white matter lesions in CADASIL has been reported to be distinct from those in patients with ischemic leukoaraiosis and Binswanger's disease. In earlier European studies, diagnostic significance of white matter lesions in the temporopolar region (Tp), medial frontopolar region (Fp) and external capsule (EC) was stressed in diagnosing CADASIL. More recently, however, high sensitivity and specificity of Tp lesions have been demonstrated. In Japan, prevalence of CADASIL is lower, and those of ischemic leukoaraiosis and Binswanger's disease, likely related to small artery disease, are much higher than in Caucasian countries. Therefore, we examined the frequencies of CADASIL-associated lesions in 17 non-demented patients with ischemic leukoaraiosis and 20 patients with Binswanger's disease. The Binswanger's disease group showed a significantly lower scores for Hasegawa Dementia Rating Scale Revised (HDSR) and a higher prevalence of hypertension, compared to the ischemic leukoaraiosis group. There was only 1 patient with Tp lesions in each group, while Fp lesions were found in 12 % and 50% in the ischemic leukoaraiosis group and Binswanger's disease group, respectively, and EC lesions in 59% and 80%. These results indicated that Tp lesions were useful diagnostic marker in diagnosing CADASIL, whereas Fp and EC lesions were non-specifically observed.