CT AND REGIONAL CEREBRAL BLOOD FLOW IN ESTIMATION OF THE PROGNOSIS OF APHASIC SYMPTOMS DUE TO CEREBROVASCULAR DISEASE

Abstract

It is important to estimate the prognosis of aphasic symptoms due to cerebrovascular disease in the early stage. CT and regional cerebral blood flow (rCBF) study were performed in 30 aphasic cases with left-sided ischemic cerebrovascular disease within a month after the onset; 10 cases were cerebral thrombosis, 10 were recanalized cerebral embolism and 10 were cerebral vasospasm following subarachnoid hemorrhage respectively. Regional cerebral blood flow was studied as to mean hemispheric value (mean-CBF) and as to the average rCBF of 3 detectors in the frontal region including Broca's area (F-rCBF) and that in the temporal region including Wernick's area (T-rCBF). The severity of aphasic symptoms was evaluated according to Hirano's classification and the outcome was graded into two groups. One was a group of favorable recovery, and another was a group of poor recovery.(1) Fourteen patients showed favorable recovery, who were considerably younger than 16 patients with poor recovery.(2) In the group of favorable recovery, 4 patients showed no obvious low density areas on CT, 3 patients showed small or moderate low density areas which were smaller than 3 centimeter in their longer diameter, and 7 patients had low density areas in the subcortex or the white matter on CT. On the other hand, in the group of poor recovery, 9 patients had large low density areas which were larger than 3 centimeter in their longer diameter and 7 patients had subcortical low density areas. The patients with cerebral atrophy or bilateral involvement also showed poor recovery. Above all, it was considered to be one of good prognostic factors that there was no obvious low density area on CT or small or moderate cortical lesion smaller than 3 centimeter in its longer diameter. On the contrary, it seemed to be a poor prognostic factor to have large cortical lesion on CT.(3) In cerebral thrombosis, there was no marked change of rCBF in the early stage. The average of mean-CBF in 3 patients with favorable recovery was 36.0±11.6ml/100g/min, and it was predominantly higher than that in 7 patients with poor recovery. The average of F-rCBF was 34.3±12.6ml/100g/min and the average of T-rCBF was 35.2±11.6ml/100g/min in the 3 patients, and both of them were significantly higher than those in the 7 patients with poor recovery (p<0.05). Consequently, rCBF as high as 36ml/100g/min was thought to be “sufficient flow level for favorable prognosis” in cerebral thrombosis.(4) Marked variation of rCBF in recanalized embolism in the early stage made it difficult to find a certain correlation between rCBF and the prognosis of aphasic symptoms.(5) In cerebral vasospasm, there was a tendency of rCBF to be increased over the third week of the onset which was thought to be a stage of resolution of spasm. Six patients with favorable recovery had significantly higher mean-CBF than 4 patients with poor recovery (p<0.05) . The average of mean-CBF in the 6 patients was 38.5±7.4ml/100g/min. The average of F-rCBF in the 6 patients was 37.9±9.3ml/100g/min, which was significantly higher than that in the 4 patients (p<0.05). Accordingly, “sufficient flow level for favorable prognosis” was considered to be about 38ml/100g/min in cerebral vasospasm.