Aneurysm embolization using detachable coils under intravascular ultrasonography guidance: An in vitro feasibility study

Background: Intravascular ultrasonography (IVUS) has been used for guiding intravascular stent placement in interventional cardiology. Objective: To evaluate the feasibility of aneurysm embolization by using detachable coils under IVUS guidance. Methods: IVUS-guided embolization in conjunction with fluoroscopic imaging and subsequently alone were performed in a silicone model with a side wall aneurysm. IVUS-guided embolization in conjunction with fluoroscopic imaging was also used in an in vitro model of a side wall aneurysm created using sheep vessels. The visibility of the aneurysm, microcatheter, and coils ascertained by the IVUS was graded as excellent, good, or poor based on visualization of these items as distinct structures. The agreement between simultaneously acquired angiographic and IVUS images for detecting increasing intra-aneurysmal coil mass and coil prolapse was assessed in 10 and 6 simultaneously acquired angiographic and IVUS images, respectively. Results: IVUS measurements of the aneurysm dimensions strongly correlated with standardized dimensions and measurements acquired by contrast angiography (Pearson coefficient of 0.96 and 0.99 for silicone model and arterial segment model, respectively). IVUS visualization of the aneurysm, microcatheter tip, and coil loops were graded as excellent in the silicone aneurysm model and good in the carotid artery model. The agreement between simultaneously acquired angiographic and IVUS images was very high for detecting increasing intra-aneurysmal coil mass (Spearman rank correlation coefficient of 0.98) and coil prolapse (83% agreement). Conclusion: IVUS guidance during aneurysm embolization may improve the procedure by providing intravascular aneurysmal measurements and visualization of devices used in the procedure.