Unruptured cerebral aneurysms can represent a significant health risk for patients if not properly diagnosed and treated. A study was carried out to determine if significant geometrical differences could be measured between a soft (close to the rupture) aneurysm and a stiff (healthy) aneurysm. The biomechanical properties of soft and stiff tissues of the aneurysm sac were determined experimentally. Image processing of MRI scans was carried out in Simpleware ScanIP to create a model suitable for simulating fluid-structure (FSI) interactions and evaluation of tissue rupture risk based on its mechanical properties.
IRRAs Technology, Philips Healthcare, University of Montpellier:
M. Sanchez • D. Ambard • V. Costalat • S. Mendez • F. Jourdan • F. Nicoud
The geometry of the aneurysm was obtained from an MRI patient scan. This data was imported into ScanIP, where automated thresholding and floodfill tools were used to separate out regions of interest, keeping only the parent artery. Cropping was then employed to reduce the region of interest for analysis. A low-pass (Gaussian) filter was applied to segmented data to reduce the noise-to-signal ratio and smooth the image. Processed image data was exported to ANSYS© for further analysis.
Boundary conditions were set for modelling fluid structure interaction (FSI) on the mechanical properties of aneurysm tissue material. Simulations were carried out in ANSYS to determine whether significant geometrical differences are measurable between a soft (close to the rupture) aneurysm and a stiff (healthy) aneurysm. Differences were observed based on volume variations and maximal mesh displacements for two aneurysm models along a typical cardiac cycle, and in the context of parametric tests.