Clinical Relevance of Initial Hounsfield Unit Values in Predicting Outcomes and Complications of Aneurysmal Subarachnoid Hemorrhage.

OBJECTIVES: This study aimed to evaluate whether the initial Hounsfield unit value (IT-HUV), easily obtained from non-contrast CT, serves as a reliable predictor not only for symptomatic vasospasm (SVS) but also for delayed cerebral ischemia (DCI) and overall prognosis in patients with aneurysmal subarachnoid hemorrhage (SAH). METHODOLOGY: A retrospective cohort of 95 patients with aneurysmal SAH who underwent craniotomy clipping and completed rehabilitation between January 2010 and December 2019 was analyzed. Associations between radiological parameters and functional outcomes (modified Rankin Scale (mRS)), as well as DCI and SVS, were assessed using univariate and multivariate analyses. RESULTS: Of the included patients, 27 (28.4%) had poor outcomes (mRS 4-5), 20 (21.1%) developed DCI, and 19 (20%) experienced SVS. Significant correlations were observed between IT-HUV and mRS (P < 0.01), SAH clearance (P = 0.02), and Hijdra sum scores (P = 0.03); between DCI and IT-HUV (P < 0.01), postoperative HUV (P = 0.02), and Hijdra sum scores (P < 0.01); and between SVS and all variables (SAH clearance: P = 0.04; others: P < 0.01). IT-HUV was the strongest radiological predictor for mRS, DCI, and SVS, with optimal thresholds around 46.2-46.9. CONCLUSIONS: IT-HUV provides a practical and reliable imaging biomarker for predicting prognosis, DCI, and SVS in patients with aneurysmal SAH. Incorporating IT-HUV into routine assessments may enhance risk stratification and guide individualized treatment strategies.