We hypothesized that CISCO is superior to modified Fisher score (mFS) in predicting vasospasm, as it better quantifies blood clot burden in the basal cisterns.

Cerebral vasospasm is associated with increased morbidity in aneurysmal subarachnoid hemorrhage (aSAH). Cisternal score (CISCO) has previously demonstrated to have good accuracy in predicting ventriculoperitoneal shunt requirement in patients with aSAH.

We performed a post hoc analysis of a retrospective study of patients with aSAH admitted to an academic center from 2016 through 2021. Data was collected prospectively as part of a quality improvement project. Vasospasm was defined based on transcranial Doppler criteria. CISCO was constructed based on quantification of blood clot thickness in the basal cisterns (interpeduncular, ambient, crural, prepontine, interhemispheric cisterns, and bilateral Sylvian fissures) on admission head CT scans. Receiver operating characteristics (ROC) curve analysis was performed to compare accuracy of CISCO with mFS in predicting vasospasm.

We included 176 patients with aSAH who had radiographic assessments with complete clinical data. Mean age was 54.9 years [SD 12.8] and 57% were female. Vasospasm was observed in 30% of patients. CISCO ranged from 0 to 10 with a median of 3 [IQR 1-5]. Higher CISCO was associated with higher risk of vasospasm (odds ratio 1.29 per point increase, 95% CI 1.17-1.49; p=0.001). ROC curve analysis revealed that CISCO had higher accuracy in predicting vasospasm compared to mFS but the difference was not significant (AUC 0.67, 95% CI 0.59-0.76 vs 0.60, 95% CI 0.52-0.68; p=0.10).

CISCO has comparable accuracy with mFS score in predicting vasospasm in aSAH. Quantification methods using fully automated volumetric measurement techniques may further enhance its accuracy in predicting vasospasm in aSAH. Further studies are needed to test this hypothesis and to explore the utility of CISCO use in clinical practice.