Comparison of dynamic CT and stable xenon CT in ischemic cerebrovascular disease.

PURPOSE To investigate a new hemodynamic parameter that can be obtained by dynamic CT and that reflects cerebral blood flow (CBF), in patients with ischemic cerebrovascular disease.

METHODS CBF and hemodynamic parameters including the area under the time-dependent contrast-medium dilution curve (A) and mean transit time (MTT) were measured in 23 patients with ischemic cerebrovascular disease. They included 17 patients in the chronic stage (more than 1 month after onset) and six with acute occlusion of the internal carotid or middle cerebral artery (within 24 hours of onset). CBF measurement was conducted by inhalation of stable xenon during CT scan and the hemodynamic study was performed using dynamic CT.

RESULTS CBF in the territory of the middle cerebral artery had an inverse correlation with MTT. (A) divided by (MTT) defined as (f) had a significantly positive correlation with CBF (MTT = 18.66 - 0.495.CBF + 0.005.CBF2, r = .730, P < .001).

CONCLUSION This parameter (f) is thought to represent a relative CBF and it can be used in evaluation of the hemodynamic status in ischemic cerebrovascular disease.