Temporal Pattern of Radiological Resolution in Chronic Subdural Hematoma After Middle Meningeal Artery Embolization: A Prospective 2-Center Study.

BACKGROUND Middle meningeal artery embolization (MMAE) treats chronic subdural hematoma (cSDH) by devascularizing the hematoma membrane, but the timing of radiological resolution remains incompletely defined. This prospective 2-center study evaluated computed tomography (CT) outcomes at 1 and 3 months after MMAE in Vietnam. MATERIAL AND METHODS Consecutive patients treated from November 2021 through December 2024 were enrolled. Maximum hematoma thickness and midline shift were measured on baseline imaging and follow-up non-contrast-enhanced CT. Paired measurements were compared using paired t tests. Analyses were performed at the hematoma level using available paired observations. RESULTS The cohort included 67 patients with 90 cSDHs. Follow-up CT was available for 76 hematomas at 1 month and 40 at 3 months. Mean hematoma thickness decreased from 14.2±5.3 mm at baseline to 8.7±10.2 mm at 1 month and 3.5±5.6 mm at 3 months (both P<0.001). Mean midline shift decreased from 6.1±4.3 mm to 0.81±1.54 mm and 0.69±1.93 mm, respectively (both P<0.001). Complete resolution was observed in 12 of 76 hematomas (15.8%) at 1 month and 23 of 40 (57.5%) at 3 months. CONCLUSIONS MMAE was associated with a gradual reduction in hematoma thickness and midline shift among hematomas with available follow-up imaging. These findings suggest that residual hematoma on early post-treatment imaging may not necessarily indicate treatment failure. However, the delayed radiological trajectory should be interpreted cautiously because 3-month imaging follow-up was incomplete and may be affected by attrition bias.