Acetazolamide vasoreactivity in persistent vegetative state and vascular dementia evaluated by transcranial harmonic perfusion imaging and Doppler sonography.

Abstract

To clarify the pathophysiological differences of the cerebrovascular reserve capacity in relation to cerebral cognitive impairments between persistent vegetative state (PVS) and vascular dementia (VD), we evaluated acetazolamide (ACZ) vasoreactivity testing by transcranial harmonic perfusion imaging (HPI) and Doppler sonography (TCD). The subjects were 11 adult patients with severe cognitive impairments (4 PVS, 7 VD). TCD mean velocity (Vm) in the middle and posterior cerebral artery (MCA, PCA) and peak intensity (PI), area under curve (AUC), and mean transit time (MTT) analyzed by HPI time-intensity curves in the bilateral temporal lobe (TL), basal ganglia (BG), and thalamus (Th) were evaluated before and after ACZ administration. Resting values and relative changes (%delta) of TCD and HPI parameters were compared between PVS and VD. a) Resting values: There were no significant differences between the two groups. b) Vasoreactivity: 1) PVS: %delta Vm decreased in the left PCA and MCA. %delta PI/AUC/MTT decreased in the left TL and bilateral BG. 2) VD: %delta PI/AUC decreased in the right TL. %delta MTT tended to decrease in the right side. ACZ vasoreactivity tests by transcranial HPI and TCD allowed bedside, non-invasive, quantitative evaluation of the pathophysiology of cognitive function impairment and treatments, in relation to cerebrovascular reserve capacity in PVS and VD.