Complex Alterations of Intracranial 4-Dimensional Hemodynamics in Vein of Galen Aneurysmal Malformations During Staged Endovascular Embolization.

Abstract

Vein of Galen aneurysmal malformations (VGAMs) are rare congenital cerebral arteriovenous shunts often treated by staged endovascular embolization early in life. Treatment-induced changes in intracranial hemodynamics and their impact on the clinical management of VGAM patients remain unclear. To evaluate hemodynamic alterations in the cerebral arterial and venous network in pediatric patients with VGAMs during staged embolizations. Serial 4-dimensional flow magnetic resonance imaging (21 scans) was performed in 6 VGAM patients (3 female; mean age, 2.1 ± 4.0 years) undergoing staged embolization. Time-integrated pathlines were used to visualize 3-dimensional blood flow changes in intracranial arterial and venous systems. Total cerebral arterial inflow (flow in bilateral internal carotid arteries plus basilar artery), arteriovenous shunt flow, and blood flow in other major cerebral arteries (middle cerebral artery; posterior cerebral artery) were quantified for all patients. Intracranial 3-dimensional blood flow visualization demonstrated marked reduction of arteriovenous shunting and distinct hemodynamic alterations after embolization. From baseline to endpoint embolization, total cerebral arterial inflow dropped by 40.2% (from 22.70 ± 6.54 mL/s to 13.57 ± 4.87 mL/s), corresponding to arteriovenous shunt flow reduction of 73.5% (from 9.69 ± 6.16 mL/s to 2.57 ± 3.79 mL/s). In addition, the ipsilateral posterior cerebral artery/middle cerebral artery flow ratio decreased by 86.9% (from 4.20 ± 6.28 to 0.55 ± 0.23). Hemodynamic alterations in VGAMs after embolization can be visualized and quantified using 4-dimensional flow magnetic resonance imaging. Cerebral arterial inflow and arteriovenous shunt flow reduction and complex flow redistribution after embolization illustrate the potential of 4-dimensional flow magnetic resonance imaging to better evaluate the efficacy of interventions and monitor treatment effects.