Difference in blood flow volume of the common carotid artery between vascular and non-vascular dementia detected by colour duplex sonography.

Using colour duplex sonography, blood flow volume in the common carotid artery was measured in 72 demented patients and 28 normal controls. Thirty-five patients with a Hachinski's ischaemic score of 7 or above and marked ischaemic lesions on CT were assigned to the vascular dementia (VD) group. Thirty-three patients with probable Alzheimer's disease according to the NINCDS-ADRDA criteria, 2 patients with Parkinson's disease, 1 patient with spinocerebellar degeneration, and 1 patient with Pick's disease were assigned to the non-vascular dementia (nonVD) group. The sum of blood flow volume in the bilateral common carotid arteries (CCA flow) in the nonVD group and in the VD group was lower than that in the control group. The CCA flow in the VD group was lower than that in the nonVD group. Comparison of patients matched for both age and the Hasegawa's dementia rating scale also revealed lower CCA flow in the VD group than in the nonVD group. Linear discriminant function analysis showed that nearly 90% of the demented patients were correctly diagnosed as having VD or as having nonVD. These results show the usefulness of colour duplex sonography in the differential diagnosis of patients with dementia.