Objective Pre-operative embolization of meningiomas remains controversial. Prior studies have shown that the degree of devascularization on angiography is not significantly correlated with intraoperative blood loss. This study examines pre and post-embolization MRI enhancement as an improved metric for assessing the degree of embolization.

Methods We retrospectively analyzed patients who underwent preoperative embolization for intracranial meningiomas at the Barrow Neurological Institute from 2007 to 2017. Two cohorts were analyzed based on the degree of devascularization observed (>/= 50% vs. <50%).

Results 84 meningioma patients underwent preoperative embolization. 35 (42%) had post-embolization MR imaging prior to surgical resection. The mean lesion diameter was 4.9 cm (±1.3) and, intraoperatively, the mean blood loss was 576 ml (±341). Based on MR imaging, angiography overestimated devascularization in 22 patients (63%). 17 (49%) patients were found to have a >/= 50% decrease enhancement on contrasted post-embolization MRI which was associated with lower mean intraoperative blood loss [444 ml vs. 700 ml in 17 patients with <50% devascularization (p=0.025)]. On angiography, 22(63%) patients demonstrated >/= 50% devascularization during embolization. These patients did not statistically differ in intraoperative blood loss as compared to those with <50% devascularization on angiography. On univariate analysis, patients with <50% decrease in enhancement on contrasted post-embolization MRI had 9 times greater odds of having at least 500 cc of intraoperative blood loss during resection (CI 1.6–54, p=0.012). Additionally, on multivariate stepwise logistic regression analysis <50% decrease enhancement on contrasted post-embolization MRI was found to be a predictor of at least 500 cc of blood loss (OR 9.4, p =0.012), but <50% devascularization on angiography was not.

Conclusion Post-embolization contrasted MRI is a better predictor of intraoperative blood loss during meningioma resection than post-embolization angiography, which overestimates the degree of devascularization.

Disclosures J. Catapano: None. C. Pryzbylowski: None. A. See: None. A. Whiting: None. M. Labib: None. N. Rubel: None. V. Fredrickson: None. A. Ducruet: None. F. Albuquerque: None. N. Sanai: None.