Prompt volumetric responses following preoperative embolization of skull base meningiomas: association with intratumoral contrast enhancement loss

OBJECTIVE: The role of preoperative embolization for skull base meningiomas remains controversial because potential surgical benefits must be balanced against endovascular procedural risks. Although embolization may induce early tumor volume reduction, evidence in skull base meningiomas remains limited. This study evaluated prompt volumetric responses after preoperative embolization and their association with intratumoral contrast enhancement loss on magnetic resonance imaging (MRI). METHODS: This retrospective study included 82 consecutive patients with skull base meningiomas who underwent preoperative endovascular embolization followed by surgical resection at a single institution between September 2013 and March 2025. Tumor volumes were measured on contrast-enhanced T1-weighted MRI obtained pre- and post-embolization. Individual volumetric responses were evaluated, and patients were categorized into four groups according to the degree of intratumoral contrast enhancement loss. Neurological complications were assessed. RESULTS: Tumor volume was significantly reduced after embolization (18.9 ± 14.2 mL vs 17.3 ± 13.7 mL, P < .001), with a mean reduction rate of 10.5 ± 12.4%, within a mean interval of 4.1 ± 1.8 days after embolization. Tumor volume decreased in 74 of 82 patients (90.2%). Volumetric responses exhibited substantial heterogeneity, ranging from −34.5% to 41.1%. Greater intratumoral contrast enhancement loss was associated with larger volume reduction rates (P = .04). Transient neurological complications occurred in 4 patients (4.9%), and permanent deficits occurred in 2 patients (2.4%). CONCLUSIONS: Preoperative embolization of skull base meningiomas was associated with early tumor volume reduction within days, although the magnitude of response varied substantially among tumors. Intratumoral contrast enhancement loss on post-embolization MRI was associated with greater tumor volume reduction and may serve as a semiquantitative imaging correlate of reduced tumor vascularity/perfusion after embolization.