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

Abstract

Background

Intracranial aneurysms (IAs) are preventively treated with flow-diverting stents (FDs), but complications persist, necessitating safer, customized FDs. While 4D flow magnetic resonance imaging (MRI) can evaluate FD treatment efficiency, metal artifacts from FDs compromise flow assessments.

Purpose

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.

Methods

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.

Results

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.

Conclusion

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.