The relationship between vasospasm and subsequent cerebral infarction detected by CT scans. Influence of aging on CT findings

We analyzed the type and the distribution of low density areas (LDAs) on CT scans caused by vasospasm, and investigated the relation between LDAs and clinical features, focusing on the influence of aging on CT findings. The subjects of this study are 159 patients (70 males and 89 females) who underwent aneurysm surgery within 7 days after the onset of hemorrhage over the past 14 years and were followed up by sequential CT scans. They were divided into 2 aged groups: ≤59 yrs (96 patients) and 60 yrs ≤ (63 patients). Of the 159 patients, 55 (35%) developed symptomatic vasospasm. Subsequent CT scans showed 66 LDAs in 42 patients (26%). There was no significant difference in incidence of symptomatic vasospasm and LDAs between the 2 age groups. Multiple LDAs and bilateral involvement were frequently observed in the aged group. We advocated the following classification for the appearance of LDAs: Major type, branch type, perforator type, subcortical type and watershed type. The major type often appeared as a single LDA. In contrast, most of the subcortical type and a number of the Branch and Perforator types were concomitant with other types of LDAs. The Watershed type was not observed alone. The outcome or the Major type was significantly worse than that of other types of LDAs. The outcome of the Branch and Perforator types was not unfavorable unless eloquent areas were involved. However, the Subcortical and Watershed types were usually accompanied by other types of LDAs that caused poor prognosis. In the aged group. the Subcortical and Watershed types were frequently observed. This finding suggests that elderly patients may lack sufficient compliance to tolerate ischemic insult after vasospasm. (author)