Patient-specific geometries of cerebral aneurysms were reconstructed from 3D rotational angiography images.13 (link) Digital subtraction imaging was performed by use of a constant injection of contrast agent at 24 mL/s for a 180° rotation in 8 seconds. Imaging was performed at 15 frames per second. Data from these images was transferred to a workstation (Phillips Healthcare, Best, The Netherlands) and reconstructed into 3D voxel data with the use of the standard proprietary software. 3D reconstructions were compared with views from the conventional angiogram to assess the completeness of the rendering. Cases with incomplete rendering or inadequate filling of the parent artery or the aneurysm were discarded.
Unstructured grids composed of tetrahedral elements were generated with a resolution of approximately 0.1 mm, resulting in grids of roughly 2–5 million elements. Vessel walls were assumed rigid, and blood flow was considered incompressible and Newtonian. Numeric solutions of the unsteady 3D Navier-Stokes equations were obtained under “typical” pulsatile flow conditions.14 (link) The inlet boundaries of all models were located in the internal carotid artery, the vertebral artery, or the basilar artery.
Two cardiac cycles were simulated with a time-step size of 0.01 second for a heart rate of 60 bpm. The analysis in this work was based on 100 snapshots of the velocity vector field generated during the second cycle. IA necks were identified on the reconstructed vascular models and used to label the aneurysm and the parent artery.15 (link) Subsequent flow characterizations were restricted to the aneurysm.
Unstructured grids composed of tetrahedral elements were generated with a resolution of approximately 0.1 mm, resulting in grids of roughly 2–5 million elements. Vessel walls were assumed rigid, and blood flow was considered incompressible and Newtonian. Numeric solutions of the unsteady 3D Navier-Stokes equations were obtained under “typical” pulsatile flow conditions.14 (link) The inlet boundaries of all models were located in the internal carotid artery, the vertebral artery, or the basilar artery.
Two cardiac cycles were simulated with a time-step size of 0.01 second for a heart rate of 60 bpm. The analysis in this work was based on 100 snapshots of the velocity vector field generated during the second cycle. IA necks were identified on the reconstructed vascular models and used to label the aneurysm and the parent artery.15 (link) Subsequent flow characterizations were restricted to the aneurysm.
