[The usefulness of carotid artery ultrasonography in patients with Binswanger's encephalopathy].

Carotid artery ultrasonography (B-mode and Duplex method) was conducted in 49 cases of Binswanger's encephalopathy (group B) to compare with 189 cases of lacunar infarction (group L). With B-mode method, there was no significant difference in the amount of plaque between group B and group L, but the inner diameter of the common carotid artery was greater in group B. Using Duplex method, we measured maximum systolic flow velocity (Max), minimum diastolic flow velocity (Min) and time velocity integral (TVI). We found that those data were consistently lower in group B than in group L, with a correlation to the severity of mental impairment. The decrease in Max in group B, which has diffuse arteriosclerosis, indicates a decline in cardiac function, while the decrease in Min indicates an increase of intracranial small vessel resistance. The lower TVI in group B is thought to reflect a loss of velocity in cerebrovascular circulation due to the decrease in Max and Min. Carotid artery ultrasonography thus proved useful in evaluating the pathogenesis and progression of the disease.