Appraisal of the angiographic circulation time as an index of cerebral blood flow.

The relationship of the brain angiographic mode circulation time (AVCT) to the mean transit time of the vascular indicator C15O-labeled hemoglobin (tc15o) and the regional cerebral blood flow (rCBF) as measured by the clearance of the diffusible tracer H2-15O was examined in 38 patients with selected cerebral diseases. The results demonstrate a predictable relationship does exist between the rCBF and tc15o. This relationship is linear when plotted as tc15o vs. 1/CBF. Further, tc150 can be estimated with sufficient accuracy from the AVCT to permit at least a qualitative assessment of rCBF from the cerebral angiogram.