Peritumoral edema and imaging markers of aggressiveness in intracranial meningiomas: A combined predictive model

Introduction Peritumoral brain edema (PTBE) is a clinically significant finding in meningiomas, yet its relationship with radiological features and tumor biology remains incompletely understood. This study characterizes imaging features across a diverse meningioma cohort, emphasizing correlations between histological subtypes, PTBE severity, and markers of tumor aggressiveness. Methods We retrospectively evaluated 48 intracranial meningiomas from a radiological-pathological database. Imaging features and WHO histological subtypes were systematically evaluated. The edema index (EI) was calculated as the edema-to-tumor volume ratio. ROC analysis evaluated imaging features for predicting disproportionate edema (EI > 3.0), followed by bootstrap resampling internal validation (1,000 replicates) with optimism correction. Results Microcystic (mean EI 4.8 ± 1.9) and angiomatous (mean EI 5.2 ± 2.1) meningiomas demonstrated higher EIs versus other WHO grade I subtypes ( ), with 100% showing EI > 3.0. Prominent flow voids correlated with PTBE severity ( ). Loss of arachnoid plane and irregular margins occurred in 80–100% of microcystic/angiomatous cases versus 16.7% of meningothelial cases ( and ). A combined model (loss of arachnoid plane, flow voids, irregular margins) demonstrated strong discrimination for disproportionate edema (AUC = 0.91, 95% CI: 0.81–0.97; 87.5% sensitivity, 83.3% specificity; optimism-corrected AUC ≈ 0.86; absolute volume AUC ≈ 0.87). Psammomatous meningiomas showed minimal edema (mean EI 0.8 ± 0.3). Conclusion Specific imaging features correlate with histological subtypes and predict aggressiveness. Microcystic and angiomatous subtypes exhibit severe PTBE and aggressive radiological traits despite WHO Grade I status. Identifying an "aggressive phenotype" may aid preoperative risk stratification and surgical planning.