Research Training Group 2154 - Materials for Brain

Project 2b: Mariya Pravdivtseva

Thin-film flow-diverter stents in blood vessel models

Aneurysms of brain arteries are prone to rupture and can lead to life-threatening bleeding. Depending on the aneurysm form and location different treatment options can be used such as surgical care using vascular clips, minimal-invasive endovascular therapy with the introduction of spirals (coils) into the aneurysm sac or stents into the vessel near the aneurysm neck. Any type of treatment can lead to complications during the operation and after. These are for instance recanalization of the coils, regrowth of the aneurysm or closing the apparent vessel by stent.
The current project P2b collaborates with Project 2 “Thin-film stents for neurovascular implants for aneurysm therapy”. The aim of this project is to investigate how the rate of complications can be reduced after endovascular therapy of aneurysm and thus the rate for permanent remediation can be increased. This project is divided into two main parts, first is development of flow-diverter-stents (P2a), and the second (P2b) concentrates on investigating the influence of stents on the flow dynamics in a realistic flow models using different methods.
In order to use a realistic flow model, various patient-based aneurysm data sets are obtained using high-resolution angiographic 3D MRA. These are used to produce 3D printed models. These flow models are investigated on the one hand with advanced flow-sensitive MR angiographic techniques (4D flow MRI) and on the other hand with conventional angiographic studies (2D phase-contrast MRA, CTA, DSA). Flow diverter stents can be inserted into the flow models and therefore changes of the hemodynamics parameters between models with and without stent can be investigated. The same model can be printed several times with high reproducibility of its geometry, thus it is possible to compare different designs of flow-diverter stents keeping the experimental conditions unchanged