Background Vein of Galen malformation (VOGM) is a rare, life-threatening vascular malformation in neonates and is treated with embolization. However, even at the most experienced centers, patients face high mortality and morbidity. In utero treatment options have been limited by lack of animal models or simulations.

Objective To create a novel ultrasound phantom simulator for a preclinical feasibility study of in utero fetal intervention for VOGM.

Methods Novel phantoms were designed and built in two configurations of spherical and windsock shape from cryogel material to mimic the salient vasculature of the fetal VOGM, based on real-patient fetal MR imaging dimensions. Critical anatomy was realistically mimicked within this model and transtorcular ultrasound-guided coil deployment was simulated. Each phantom model was assessed before and after treatment to evaluate coil mass deposition within the target.

Results The two phantoms underwent pretreatment T2-weighted MR imaging assessment, ultrasound-guided embolization, post-treatment MR and fluoroscopic imaging, and visual inspection of the sliced phantoms for target embolization verification. Postoperative MR scans confirmed realistic compact deposition of the coil masses within the central cavity. Phantom embolization results were submitted as part of the institutional review board and US Food and Drug Administration investigative device exemption approval for a first-in-humans clinical trial of fetal intervention for VOGM.

Conclusions A phantom simulator for fetal intervention of VOGM produces lifelike results during trial interventions, removing obstacles to feasibility and safety evaluations, typically precluded by non-availability of appropriate animal models. The study provides a proof of concept for potentially wider applications of medical simulation to enable novel procedural advancements in neurointerventions.