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

OBJECTIVE: To describe longitudinal image changes in supratentorial hemispheric meningiomas based on magnetic resonance imaging after preoperative embolization using calibrated microspheres. METHODS: 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. RESULTS: 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 mm(2)/s) decreased significantly within 6 hours (696 +/- 115 mm(2)/s, P = 0.0008) as well within 48 hours (752 +/- 134 mm(2)/s; P = 0.0147). Baseline mean ratio of relative cerebral blood volume (rCBV)(tumo)(r)/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)/rCBFwhite matter of 1.19 +/- 0.8; P = 0.003). The viable enhanced baseline mean tumor volume (54.3 +/- 34.9 mm(3)) was sustainably and significantly diminished within 6 hours (26.6 +/- 20.8 mm(3); P = 0.02) and 48 hours (29.7 +/- 22.5 mm(3); 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). CONCLUSIONS: Preoperative meningioma embolization with calibrated microspheres is safe and effectively induces a significant and sustainable tissue transformation over 48 hours.