We analyzed circulation time (rABCT) and vascular volume density images obtained by angio-computerized tomography (angio-CT) in 63 patients with small deep cerebral infarctions. Abnormalities in the rABCT image were found in 88% of the patients and in the vascular volume image in 48%. Two groups with different clinical pictures were picked out by rABCT changes: one with major-vessel involvement, the other with small-vessel involvement. The perfusional changes found were mainly due to altered vascular canalization rather than to altered vasomotility. The hemodynamic theory could explain the spatial relations between perfusion changes and CT hypodense areas without needing assumptions linking blood flow and metabolism.