Changes in cerebral blood flow following rupture of intracranial aneurysms. Part 1, Mean hemispheric values (author's transl)

Abstract

Ninety-five studies of regional cerebral blood flow were performed in 52 patients with ruptured intracranial aneurysms. Cerebral blood flow was measured by the 133Xe clearance method using multiple detectors and regional values were averaged for each patient to obtain mean hemispheric values (mean CBF). The changes in mean CBF were analyzed under various pathophysiological conditions following rupture of intracranial aneurysms and were discussed with special reference to clinical prognosis. The results were as follows: 1) In general, diffuse reduction in CBF was found and continued for a long time in spite of improvement of clinical grades. Reduction in flow was bilateral but was greater on the side of the lesion in 3 cases studied. 2) The degree of reduction correlated well with the clinical grade of neurological deficits. The values of mean CBF in Grades I . II, III and IV patients were 39.4±7.6, 32.7±6.0, 25.7±5.8 ml/100g/min, respectively. 3) Arterial spasm was often associated with a reduction in mean CBF. A good correlation of spasm with decreased mean CBF was found in 8 cases studied both at the presence and at the absence of spasms; the values were 29.6±5.0 and 39.3±6.5 ml/100g/min, respectively. Reduction in mean CBF, however, was found even at the absence of spasm and spasm was not necessarily associated with depressed flow. 4) Twelve cases with intracerebral hematoma and four cases with hydrocephalus were usually associated with marked reduction in mean CBF, 29.5±5.3 and 27.0±3.7 ml/100g/min, respectively. 5) Patients without neurological deficits whose preoperative mean CBF were over 30 ml/100g/min showed good clinical results. The mean CBF ranging 20 to 40 ml/100g/min was found in patients with some neurological deficits. Marked reduction in preoperative mean CBF resulted in poor clinical prognosis. It was concluded that analysis of cerebral blood flow was useful in determining the time for surgical intervention and indicative of a good prognosis of cerebral function and survival.