Predictive performance of non-contrast CT signs for hematoma expansion: A comparative analysis across traditional,...

Hematoma expansion (HE) is a critical determinant of neurological deterioration after spontaneous intracerebral hemorrhage (ICH). While non-contrast CT (NCCT) signs (Blend sign, Black hole sign, Hypodensities) are established predictors under traditional parenchymal-volume-based HE definitions, their performance under a revised composite definition that includes intraventricular hemorrhage (IVH) expansion remains unvalidated.

In a retrospective cohort of 685 spontaneous ICH patients, HE was assessed using three definitions: traditional (parenchymal increase > 6 mL or > 33%), revised (traditional criteria and/or IVH expansion [≥ 1 mL or new IVH]), and conservative revised (IVH threshold > 2 mL). Multivariable logistic regression evaluated the independent association of NCCT signs with each definition. Model discrimination was compared using ROC analysis.

HE incidence was 17.08% (traditional), 21.90% (revised), and 20.15% (conservative revised). All three NCCT signs remained strong, independent predictors across all definitions after full adjustment (all p < 0.001), with no significant multicollinearity. The combined predictive model (clinical variables + all three signs) showed excellent and comparable discrimination for traditional (AUC = 0.867) and revised (AUC = 0.821) definitions (P = 0.13). A strong, identical inverse relationship between time-from-onset and HE risk was observed across all definitions. The revised definition captured all cases of severe HE (> 12.5 mL or > 50% growth) and identified an additional subgroup with isolated IVH expansion.

The Blend sign, Black hole sign, and Hypodensities are robust predictors of HE that generalize effectively from traditional to IVH-inclusive composite definitions. Their predictive utility, combined with the time-dependent risk profile, supports their use for early, universal risk stratification in acute ICH, irrespective of the specific HE definition employed.