Determining intra-aneurysmal flow for coiled cerebral aneurysms with digital fluoroscopy

Background and Purpose. Aneurysm geometry often dictates the success of coil embolization. A strong hemodynamic force or high intra-aneurysmal flow may indicate a high probability of recanalization. It is necessary to develop a tool that can predict and estimate the level of hemodynamic forces that coils are subject to during the procedure. Methods. A compartment model is developed to estimate the intra-aneurysmal flow after coil embolization from digital fluoroscopy. The model is based on the measured signal intensity curves for the aneurysm and adjacent artery and derives the amount of intra-aneurysmal flow reduction. A clinical case of a carotid aneurysm was used for demonstration of its ability. Results. Intra-aneurysmal flow was reduced by 70% after coil embolization, and the estimated porosity was 60%. Flow reduction was confirmed by computational fluid dynamics simulations that modeled the coiled aneurysm as a porous medium. Conclusion. Intra-aneurysmal flow reduction may be used to predict the outcome of coil embolization or possible aneurysm recurrence. A sustained high intra-aneurysmal flow prohibits complete embolization and allows recanalization of the aneurysm. The compartment model provides a reasonable estimate of intra-aneurysmal flow and hemodynamic forces on the coils.