Abstract DP343: Computed Tomography Angiography Misses One-Third of Vasospasm Cases Compared to Digital Subtraction Angiography Following Subarachnoid Hemorrhage

Vasospasm following subarachnoid hemorrhage (SAH) is a major cause of delayed cerebral ischemia, a leading contributor to morbidity and mortality. Early screening and detection of vasospasm are critical for risk stratification and guiding management decisions. Digital subtraction angiography (DSA) is considered the diagnostic gold standard, while computed tomography angiography (CTA) provides a less invasive and more widely available alternative often used for initial screening. We compared the performance of CTA versus DSA in detecting post-SAH vasospasm across 40 baseline-matched patients with paired imaging studies. Patients were stratified into groups based on whether DSA detected more vasospasm (n=24) or not (n=16). Baseline demographics and severity scores (GCS, Hunt&Hess, Modified Fisher) were similar between groups, minimizing confounders. Overall, 32.5% of vasospasm detected by DSA went undetected by CTA (p