DynaCT Enhancement of Subdural Membranes After Middle Meningeal Artery Embolization: Insights into Pathophysiology

Objective: Middle meningeal artery (MMA) embolization could be an effective method of inhibiting neovascularization of the subdural capsular membrane and preventing hematoma maintenance. We sought to better understand how the MMA might affect subdural hematoma physiology and how this process might be modified by embolization.

Methods: We performed a retrospective review of 27 patients with 29 subdural hematomas (SDHs) who had undergone MMA embolization from July 2018 to May 2019. Of the 27 patients, 8 had undergone postembolization DynaCT imaging studies and were included in the present study.

Results: The average patient age was 75 years. The baseline noncontrast-enhanced cranial computed tomography (CT) scans showed the presence of a hematoma membrane in all 8 patients. The postembolization DynaCT scans of all patients demonstrated enhancement of all 4 components (i.e., dura, capsular membrane, septations, and subdural hematoma fluid). All patients had a minimum of 60-day imaging and clinical follow-up data available. The average decrease in SDH volume at the last follow-up examination was 87% compared with that at baseline. A significant difference was found between the average baseline and average last follow-up SDH volume (P < 0.0001, paired t test) in all 8 patients. The average interval from the date of the procedure to the last follow-up scan was 89 days (range, 61-122 days). No patient experienced postembolization complications, subsequent SDH drainage, or mortality.

Conclusions: Our data lend support to the theory of contiguous vascular networks between the MMA and SDH membranes. Targeting these leaky vascular networks might remove the source of hematoma accumulation. These data add to the pathophysiological understanding of the disease and suggests potential insights into the mechanism of action of MMA embolization.