Longitudinal Imaging of Tumor Volume, Diffusivity, and Perfusion After Preoperative Endovascular Embolization in Supratentorial Hemispheric Meningiomas.

Abstract

To describe longitudinal image changes in supratentorial hemispheric meningiomas based on magnetic resonance imaging after preoperative embolization using calibrated microspheres. A total of 14 patients with symptomatic supratentorial meningiomas were included in a prospective, mono-centric, mono-arm study. Magnetic resonance imaging changes on diffusion-weighted imaging, dynamic contrast susceptibility-perfusion-weighted imaging, susceptibility-weighted imaging, and magnetization-prepared rapid acquisition gradient-echo sequence T1-weighted postcontrast sequences 6 and 48 hours after embolization were evaluated and correlated with angiographic and clinical data. The mean age of the patients was 63 ± 12.7 years with an equal female/male ratio. Twelve meningiomas were World Health Organization grade I and II tumors. After embolization, baseline apparent diffusion coefficient (901 ± 166 mm²/s) decreased significantly within 6 hours (696 ± 115 mm2/s, P = 0.0008) as well within 48 hours (752 ± 134 mm²/s; P = 0.0147). Baseline mean ratio of relative cerebral blood volume (rCBV)_tumor/rCBV_{white matter} (3.67 ± 1.83) and relative cerebral blood flow (rCBF)_tumor/rCBF_{white matter} (2.89 ± 1.57) significantly decreased after embolization within 6 hours (rCBV_tumor/rCBV_{white matter} of 1.45 ± 0.9; P = 0.0007, rCBF of 1.16 ± 0.68; P = 0.0029) and 48 hours (rCBV of 1.50 ± 1.07; P = 0.0009, rCBF_tumor/rCBF_{white matter} of 1.19 ± 0.8; P = 0.003). The viable enhanced baseline mean tumor volume (54.3 ± 34.9 mm³) was sustainably and significantly diminished within 6 hours (26.6 ± 20.8 mm³; P = 0.02) and 48 hours (29.7 ± 22.5 mm³; P = 0.035) after embolization. There was a good correlation between angiographic devascularization rate and the embolized tumor volume at 6 hours (r = 0.7; P = 0.03) and 48 hours (r = 0.78; P = 0.041). Preoperative meningioma embolization with calibrated microspheres is safe and effectively induces a significant and sustainable tissue transformation over 48 hours.