Development of 3D-printed flow-diverting stents for studying the effect of aneurysm treatment in vitro

Intracranial aneurysms (IAs) are preventively treated with flow-diverting stents (FDs), but complications persist, necessitating safer, customized FDs. While 4D flow MRI can evaluate FD treatment efficiency, metal artifacts from FDs compromise flow assessments. This study developed a protocol for fabricating 3D-printed FD replicas to test customized FDs and support MR imaging development by providing a metal-free testing platform. Simplified mesh models with varying wire diameters (0.05–0.5 mm) and cell lengths (0.07–4.74 mm) were 3D printed using stereolithography and tested under gravity. A patient-specific aneurysm model was created, with 3D-printed FDs featuring 6, 16, and 20 wires covering the aneurysm entrance. Flow reduction caused by 3D printed FDs was evaluated with 4D flow MRI and compared to a commercial FD. Printable meshes had wire diameters ≥0.05 mm, with porosities over 14% ensuring permeability. Lower porosities reduced gravity flow (4.93 ml/s vs. 28.57 ml/s for 14% and 54% porosity). Only wire sizes of 0.25 mm and 0.5 mm were accurately 3D-printed. The 3D-printed FDs reduced flow into the aneurysm sac without metal artifacts on MR images. The 20-wire FD fully occluded aneurysm flow, while the 16-wire and 6-wire FDs achieved 94% and 76% reductions, comparable to the 65% reduction of the commercial FD. The proposed workflow enables efficient 3D printing of FD replicas that match commercial FDs in performance. These 3D-printed FDs can optimize initial design parameters and support artifact-free MR imaging development for aneurysm treatment evaluation.