Newsletter 2016.2 Index
Theme : "The Conference of Fluid Engineering Division"
Subarachnoid hemorrhage is the leading cause of death or severe disability, and cerebral aneurysm is a major cause for the disease because of its rupture. Thus, the patients who have unruptured aneurysms need to be obliterated them by clipping or endovascular treatment.
Coil embolization has been one of the most popular methods to treat an unruptured saccular cerebral aneurysm because of its minimal invasiveness. In this method, thin biocompatible metal wires are inserted into an aneurysm by a catheter and the dome region is filled with this medical devices. Leading a thrombus in the aneurysm with the inserted coils, blood flowing into it is prevented and the risk of the aneurysm rupture will be decreased. However, recurrence of aneurysms after coil embolization remains as a major problem. This phenomenon means a re-inflow of blood into the aneurysm because of coil compaction, which means the coil is literally compacted into the aneurysm physically, or re-growth of the aneurysm. Clinical reports showed that around 10% - 25% aneurysms with coil were recanalized. Unfortunately, the risk assessment protocol for such procedure has not been established yet, and the mechanism has not been understood clearly either.
We characterize the hemodynamics of aneurysms before and after first embolization cases using CFD. In this study, the patient specific models of arteries and embolized coil from three-dimensional digital subtraction angiography (3D-DSA) data are used. We process hemodynamic and morphological parameters, and examined the difference of them between recanalized cases and stable cases statistically to investigate the occurrence mechanism of the aneurysm recanalization. The results indicate that some hemodynamic and morphological parameters may be factors for recanalization. From the result, we may propose the patient-specific indicator, volume embolization ratio (VER), to prevent the prospective recurrence of aneurysms.
Fig. 1 Saccular Aneurysm
Fig. 2 Illustration and Angiographic images of recanalized aneurysm
Fig. 3 Analysis Flow
Fig. 4 Result of Recanalized Case