Computation of the change in length of a braided device when deployed in realistic vessel models

Abstract

Purpose An important issue in the deployment of braided stents, such as flow diverters, is the change in length, also known as foreshortening, underwent by the device when is released from the catheter into a blood vessel. The position of the distal end is controlled by the interventionist, but know- ing a priori the position of the proximal end of the device is not trivial. In this work, we assess and validate a novel computer method to predict the length that a braided stent will adopt inside a silicon model of an anatomically accurate vessel. Methods Three-dimensional rotational angiography images of aneurysmatic patients were used to generate surface mod- els of the vessels(3Dmeshes) and then create accurate silicon models from them. A braided stent was deployed into each silicon model to measure its length.Thesamestents deployed on the silicon models were virtually deployed on the 3D meshes using the method being evaluated. Results The method was applied to five stent placements on three different silicon models. The length adopted by the real braided device in the silicon models varies between 15 and 30%from the stent length specified by the manufacturer. The final length predicted by themethodwaswithin the esti- mated error of the measured real stent length.Conclusions The method provides, in a few seconds, the length of a braided stent deployed inside a vessel, showing an accurate estimation of the final length for the cases studied. This technique could provide useful information for plan- ning the intervention and improve endovascular treatment of intracranial aneurysms in the future.