Post-procedural edema and related clinical outcomes after curative endovascular brain arteriovenous malformation embolization: an MRI-based cohort study.

Abstract

Curative embolization of brain arteriovenous malformations (bAVMs) using transarterial (TAE) and transvenous (TVE) embolization approaches has emerged over the past decade as a promising technique in high-volume centers. Although post-procedural brain edema has been observed, its incidence and clinical impact have not been systematically evaluated using objective imaging metrics. In this observational study, we retrospectively analyzed consecutive patients treated with curative intent for bAVMs, with a focus on characterizing newly developed MRI lesions. All patients underwent MRI, including diffusion weighted imaging (with apparent diffusion coefficient (ADC) mapping) and fluid-attenuated inversion recovery (FLAIR) sequences, before treatment, at 24-48 hours, and at ≥3 months' post-procedure. Vasogenic edema was defined as newly developed FLAIR hyperintensity, without ADC reduction; its volume was quantified. Primary outcome was the presence of non-pre-existing, vasogenic edema after embolization and at follow-up, comparing TAE and TVE. 55 bAVMs were included (45.5% TAE; 54.5% TVE) between January 1, 2010, and December 31, 2023. Mean post-procedural FLAIR volume was 15.9±18.3 cm³ for TAE and 17.9±23.9 cm³ for TVE at 24-48 hours after the procedure, and 4.3±7.3 cm³ for TAE and 3.4±5.9 cm³ for TVE on late MRI. No statistically significant difference was observed between techniques. A significant decrease (P<0.001) in MRI-documented brain edema was observed for both approaches between early and late MRI. Vasogenic edema was frequently observed in the early post-procedural period after both curative TAE and TVE, and significantly regressed over time.