[Dynamic pathophysiology of cerebral infarction and revascularization. III. Changes of regional cerebral blood flow]

Thirty-eight patients with occlusive cerebrovascular disease were followed with regional cerebral blood flow (rCBF) measurement, angiography and computerized tomography (CT) to know the time course of rCBF in cerebral infarction. The rCBF study was carried out by the 133Xe intracarotid injection method with 16 scintillation detectors. They were allocated to two groups according to the findings on angiograms; 15 patients having any change of occlusive lesion (the group of no-recanalization ) and 23 patients showing reopening of occluded vessels (the group of recanalization). A mass sign and an extent of cerebral infarction were observed on CT. In the group of no-recanalization, a mean value of rCBF (mean rCBF) in acute stage was well correlated to the severity of ischemic stroke. In minor completed strokes the average mean rCBF was 35.8 +/- 3.7 ml/100g/min, which is significantly higher than that in major strokes and progressing strokes of 24.8 +/- 3.9 ml/100 g/min (p less than 0.001). Sequential change of mean rCBF was not prominent in the group of no-recanalization. However, rCBF change was conspicuous in the group of recanalization. In acute stage of recanalization, rCBF were markedly affected by the presence of mass sign (cerebral edema) on CT. When CT showed midline shift of structure, mean rCBF was markedly reduced, and when without midline shift, focal hyperemic areas were sometimes observed in the revascularized area. Thus, the inhomogeneity of rCBF was characteristic in cases with recanalization. The focal hyperemia usually disappeared within one week in cases of minor stroke and lasted until 2 or 3 weeks in cases of major stroke. In chronic stage, mean rCBF decreased, and there was no significant difference of averaged rCBF between two groups. Those findings suggests that the main factor influenced on the sequential change of rCBF is reopening of occluded vessels. Regional CBF may depends both on the degree of cerebral edema and the extent of vasoparesis after revascularization. In chronic stage CBF value is not always dependent to the presence of occlusive lesion but might be reflected in the total brain function.