Perfusion Characteristics in Chronic Cerebrovascular Insufficiency

Xenon-enhanced computed tomography (XeCT) allows quantification of hemodynamic insufficiency in the setting of cerebrovascular atherosclerotic disease (CAD). However, data regarding the relationship between hemodynamic indices [cerebral blood flow (CBF) and cerebrovascular reserve capacity (CVRC)] and normal subjects (with aging) and pathology (progression of CAD or development of stroke symptoms) are limited. In this study, we analyzed 103 consecutive patients undergoing XeCT according to age, anatomical location and disease severity. We stratified anatomically defined ROIs according to a classification system that observes the presence of proximal stenosis (class I vs. class II/III) as well as the presence of neurological symptoms (class II vs. III); CBF, CVRC and hemodynamic stress distribution were calculated. Supratentorial CBF decreases significantly with age, but not infratentorially. Cortical CVRC remains stable over time. Our classification of disease severity correlated highly significantly with a decrease in supratentorial CBF and CVRC, though CVRC is less sensitive to age-related changes. Regression analysis delineated a CVRC of 34% to discriminate between ROI classes. Age-dependent perfusion characteristics in normal vascular territories were characterized. In CAD, CVRC remains the most sensitive parameter. A simplified classification of ROIs according to disease severity correlates well with established markers for hemodynamic insufficiency. It may facilitate comparison of different pathologies such as CAD and Moyamoya disease and will be the focus of further studies.