The ABCs of Subarachnoid Hemorrhage Blood Volume Measurement: A Simplified Quantitative Method Predicts Outcomes and Delayed Cerebral Ischemia

Abstract

AbstractBackgroundWe sought to develop an easy-to-use quantifiable and more precise method to estimate total blood volume in patients with aneurysmal subarachnoid hemorrhage (SAH) and explore its volumetric extent on incidence of delayed cerebral ischemia (DCI) and poor outcomes by modified Rankin Scale by hospital discharge.MethodsIn this retrospective observational cohort study, we analyzed 277 patients with SAH admitted at our Comprehensive Stroke Center between 2012 and 2022. We derived a mathematical model (Model 1) by measuring SAH basal cisternal blood volume using a ABC/2-derived ellipsoid formula (A=width/thickness, B=length, C=vertical extension) on noncontrast computed tomography (NCCT) in 5 major SAH cisternal compartments. We compared Model 1 (M1) against a manual segmentation method (Model 2) on noncontrast head CT (NCCT). Data were analyzed using logistic regression analysis,ttest, receiver operator characteristic curves (ROC), and area under curve (AUC) analysis.ResultsThere was no significant difference in cisternal SAH volume (SAHV) analysis between the two models (p=.14). Average SAHV by M1 was 7.0 mL (95% CI, 5,89-8,09) and lower for good outcome at discharge and 16.6 mL (95% CI, 13.49-19.77) for poor outcome. Volumetric analysis showed that patients with DCI had higher SAHV with 10 mL as a cutoff value (JABC-SAHV-outcome=10.0855 mL and JABC-SAHV-DCI=10.117 mL).ConclusionsA simplified ABC/2-derived method of SAH blood volume measurement is comparable to manual segmentation, and more importantly, can be performed in low-resource settings. Higher total SAH volumes by ABC/2-derived method were associated with worse outcomes and higher risk of DCI in this study population. A potential dose-response relationship of SAHV blood greater than 10mL appeared to predict worse outcomes and higher risk for DCI. A future larger prospective trial is being planned to validate these results.Subject codes[50] Cerebral Aneurysm, AVM, & Subarachnoid hemorrhage; [58] Computerized tomography and Magnetic Resonance Imaging