Residence time in intracranial aneurysms treated with coils: Experimental in-vitro analysis using PLIF.

Endovascular coiling is a common technique to treat cerebral aneurysms. The goal is to induce stagnation in the aneurysmal sac, with subsequent thrombosis and exclusion of the hemodynamics stresses on the aneurysmal wall, avoiding further remodeling and rupture. Hemodynamics in the coiled aneurysm is studied to characterize the treatment outcome. Hemodynamics metrics are often studied numerically due to the impossibility to visualize the coils in a clinical scan. In this study, we evaluate residence time (RT) in coiled aneurysms experimentally. Seven phantoms of arteries with aneurysm were used, reconstructed from clinical images. These models were coiled and rhodamine was injected in the aneurysmal sac. The parent vessel was filled with a transparent mixture (water, glycerol and sodium) with properties close to those of blood. Planar Laser Induced Fluorescence (PLIF) was used to measure the rhodamine wash-out time experimentally for each patient. RT was assessed through image analysis of the decay of the fluorescence intensity in the PLIF images. The results were compared with CFD simulations of the same coiled aneurysm. This study allows to validate the numerical model, but also to determine a surrogate for true RT in coiled aneurysm.