Virtual tests are increasingly important for the design and development of medical devices, such as stents, since they shorten the time to market. The possibilities of computational fluid dynamics (CFD) and finite element analysis (FEA), combined with contemporary imaging techniques, greatly facilitate stent research. In order to create realistic computational models to perform this research, the geometry of the stent in question and its delivery system should be very accurate. This case describes how IBiTech obtains accurate stent geometry by segmenting nano/micro-CT images and reconstructing them in 3D using the Mimics Innovation Suite. This software proved to be the perfect tool to get this very precise geometry ready for virtual testing.
Accurate Reconstruction of a StentStents are metallic, tube-like structures that are deployed in stenotic arteries to restore blood flow. The main purpose of a stent is to increase the diameter of a blood vessel by propping open the conduit. Stents are often used to alleviate diminished blood flow to organs and extremities beyond an obstruction, maintaining adequate delivery of oxygenated blood. Prior to the procedure, the stent is collapsed to a small diameter and mounted on a balloon catheter. It is then moved into the obstructed area. Subsequently, the balloon is inflated, the stent expands, locks into place and forms a scaffold which keeps the vessel open.
Gaining Insight in the Stent’s Properties
The Mimics Innovation Suite turns 3D image data into high quality digital models in an accurate and efficient way. Starting from CT, MRI or 3D Ultrasound images, the Mimics Innovation Suite offers the most advanced image segmentation, the broadest anatomical measurement options, powerful CAD tools for Engineering on Anatomy and 3D Printing, and accurate model preparation for FEA and CFD.
The authors used the Mimics Innovation Suite to study and publish virtual stent deployment using following steps:
- Transform micro-CT data into 3D reconstruction of a real-life stent
- Remesh the stent structure to a high quality surface mesh
- Export and add material properties and loading conditions to prepare for FEA solving
- Combine the stent FEA model with patient-specific anatomy from medical image data for virtual implantation