Determination of the Optimal Ratio and the Relationship Between Viscosity and Adhesion of n -Butyl Cyanoacrylate–Lipiodol–Iopamidol for Balloon-Assisted Embolization of Wide-Neck Aneurysms in Swine

Purpose To determine the optimal ratio of n -butyl cyanoacrylate–Lipiodol–iopamidol (NLI) for balloon-assisted embolization of wide-neck aneurysms in swine. Materials and Methods Sixteen NLI mixtures were prepared for in vitro studies. The viscosity of each mixture was measured for 30 min. We evaluated whether the mixtures could be injected through a microcatheter and whether they adhered to the microcatheter. In vivo, 15 wide-neck aneurysms were created on the arteries in 4 female swine. Under balloon occlusion, 7 aneurysms were embolized with NLI141 (NBCA:Lipidol:iopamidol = 1:4:1) and 8 were embolized with NLI231. We performed angiography to evaluate adhesion of NLI to the balloons or microcatheters and NLI migration. Results In vitro, the iopamidol content needed to comprise at least 1/6 of the mixture in order for NLI to be non-adhesive with increased viscosity. NLI could not be injected through a microcatheter if the iopamidol content exceeded 1/6 of the mixture. Only NLI141 and NLI231 did not adhere to the microcatheter with increased viscosity, and could be injected through a microcatheter. In vivo, neither NLI mixture adhered to the balloons or microcatheters. The migration of NLI was observed in 6 of 7 aneurysms embolized with NLI141 and in none of 8 aneurysms embolized with NLI231. Conclusion Our in vitro study revealed that the ratios of NLI that were non-adhesive and could be injected through a microcatheter were 1:4:1 and 2:3:1. The optimal ratio of NLI for balloon-assisted embolization of wide-neck aneurysms in swine was considered to be 2:3:1.