Integrating Time‐Adjusted Imaging Instability Into Functional Outcome Prediction After Intracerebral Hemorrhage: Development and Validation of the <scp>HAGIV</scp> Score

OBJECTIVE: Early risk stratification may support clinical decision-making in spontaneous intracerebral hemorrhage (ICH). We aimed to develop and internally validate HAGIV, a score integrating frequency of imaging markers (FIM), a time-adjusted non-contrast computed tomography (CT) metric of hematoma expansion, with established predictors for 90-day functional outcome in supratentorial ICH. METHODS: This prespecified prognostic modeling study used a multicenter retrospective cohort of consecutive supratentorial ICH patients with baseline non-contrast CT within 6 h of onset (January 2018-August 2022). The HAGIV score was constructed by assigning integer points according to regression coefficients from multivariable logistic regression. Discrimination for poor functional outcome (modified Rankin Scale score 3-6) was assessed using area under the curve (AUC) and compared with established ICH prognostic scores. RESULTS: HAGIV incorporated baseline hematoma volume (H), age (A), Glasgow Coma Scale score (G), frequency of imaging markers (I), and presence of intraventricular hemorrhage (V). In the derivation cohort, HAGIV achieved an AUC of 0.86, significantly outperforming the ICH (0.81), MICH (0.81), Outcome (0.72), and Landseed ICH (0.79) scores (all p < 0.001, DeLong's test). This superiority was confirmed in the validation cohort, where HAGIV maintained an AUC of 0.84 compared with 0.76, 0.78, 0.75, and 0.75, respectively. INTERPRETATION: In this predominantly small-to-moderate, supratentorial ICH cohort, HAGIV integrated FIM with established prognostic variables and improved discrimination for 90-day outcome. It may support interpretable early risk stratification for counseling and trial design, but prospective external validation is required before broader clinical implementation.