3DRA Reconstruction of Intracranial Aneurysms - How does Voxel Size Influences Morphologic and Hemodynamic Parameters.

Three-dimensional shape analysis and imagebased hemodynamic simulations are widely used to assess the individual rupture risk of intracranial aneurysms. However, the quality of those results highly depends on pre-simulative working steps including image reconstruction and segmentation. Within this study, three patient-specific aneurysms were reconstructed using three different voxel sizes (0.1 mm, 0.3 mm, 0.5 mm). Afterwards, 3D segmentations and time-dependent blood flow simulations were carried out to evaluate the impact of the reconstruction size. The results indicate that overall all voxel sizes lead to a qualitatively good agreement with respect to the aneurysm surfaces. However, deviations occur regarding the neck representation as well as the consideration of perforating arteries. Further, morphological differences lead to clear hemodynamic variations, especially for shear force predictions. The findings indicate that depending on the desired analysis, careful reconstruction parameter selection is required. Particularly, for quantitative morphology and blood flow studies, the early step of reconstruction can have a crucial effect on subsequent results.

Bringing hemodynamic simulations closer to the clinics: a CFD prototype study for intracranial aneurysms.

Computational Fluid Dynamics enables the investigation of patient-specific hemodynamics for rupture predictions and treatment support of intracranial aneurysms. However, due to numerous simplifications to decrease the computations effort, clinical applicability is limited until now. To overcome this situation a clinical research software prototype was tested that can be easily operated by attending physicians. In order to evaluate the accuracy of this prototype, four patient-specific intracranial aneurysms were investigated using four different spatial resolutions. The results demonstrate that physicians were able to generate hemodynamic predictions within several minutes at low spatial resolution. However, depending on the parameter of interest and the desired accuracy, higher resolutions are required, which will lead to an increase of computational times that still look very attractive towards clinical usability. The study shows that the next step towards an applicable individualized therapy for patients harboring intracranial aneurysms can be done. However, further in vivo validations are required to guarantee realistic predictions in future studies.