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

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSION: Vasogenic edema was frequently observed in the early post-procedural period after both curative TAE and TVE, and significantly regressed over time.