Multiparametric MRI Habitat Imaging for Preoperative Assessment of Ki-67 Proliferation Index in Meningiomas: A Multicenter Study.

Background

Preoperative assessment of meningioma proliferative activity relies on the postoperative Ki-67. Habitat imaging captures proliferative variation invisible to whole-tumor analysis by segmenting tumors into distinct subregions.

Purpose

To develop and validate a multiparametric MRI habitat imaging model for preoperative assessment of the Ki-67 proliferation index in meningiomas. STUDY TYPE Retrospective, multicenter. POPULATION Five hundred and twelve-patients (mean age 54.4 ± 10.8 years; 340 [66.4%] female) from four institutions, divided into a Training Set (n = 220) and two independent external validation sets (n = 95 and 197); Ki-67 ≥ 5% defined the high-expression group. FIELD STRENGTH/SEQUENCE 1.5-T or 3.0-T; T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), contrast-enhanced T1-weighted (CE-T1), and T2-fluid-attenuated inversion recovery (T2-FLAIR) sequences (spin echo, fast spin echo, and inversion recovery sequences). ASSESSMENT K-means clustering defined four habitats. Radiomic features were extracted to construct a Bagging-multilayer perceptron (MLP) ensemble, evaluated by receiver operating characteristic (ROC) analysis, sensitivity, specificity, decision curve analysis (DCA), and SHapley Additive exPlanations (SHAP). STATISTICAL TESTS Area under the ROC curve (AUC) with 95% confidence intervals (CIs); sensitivity, specificity, F1 score, positive predictive value (PPV), negative predictive value (NPV); DeLong tests; net reclassification improvement (NRI); integrated discrimination improvement (IDI); Brier scores; Hosmer-Lemeshow test. Two-tailed p < 0.05.

Results

Habitat-derived features, particularly textural heterogeneity in the strongly enhancing subregion, accounted for most selected features (9 of 15). The Final model achieved AUCs of 0.929 (95% CI: 0.894-0.964; Training Set), 0.903 (95% CI: 0.846-0.961; External Validation Set 1), and 0.914 (95% CI: 0.872-0.956; External Validation Set 2), significantly higher than all baseline models (ΔAUC 0.091-0.266; DeLong p < 0.05). Across cohorts, sensitivities ranged 0.651-0.843, specificities 0.874-0.911, PPVs 0.789-0.848, NPVs 0.758-0.912, and F1 scores 0.738-0.815. Compared with whole-tumor radiomics, NRI was 0.71-0.83 and IDI 0.26-0.39. DCA showed the highest standardized net benefit (0.230-0.274) at 15%-35%. Brier scores (0.106-0.152) were lower than those of the Habitat model; Hosmer-Lemeshow p values were 0.43-0.76. DATA

Conclusion

This habitat-based model may enable noninvasive preoperative assessment of the Ki-67 proliferation index in meningiomas and assist preoperative risk stratification; prospective validation is warranted. EVIDENCE LEVEL 2. TECHNICAL EFFICACY Stage 3.