Examination of the Optimal Dilution Concentration of Contrast Medium in Carotid Artery 3D Rotation Angiography (3D-RA) after CASPER Rx Placement

Abstract

Objective: Insurance coverage for carotid artery stent CASPER Rx began in September 2020. We have previously reported the usefulness of 3D-RA immediately after carotid artery stenting and at follow-up after implantation to evaluate the stent appearance and stent lumen.

Methods: Based on the results of the study on the optimal dilution concentration of contrast agent in the phantom study, images of 18 cases (11 immediately after stenting and 7 follow-up cases) that underwent 3D-RA between November 2021 and April 2022 were examined retrospectively.

Results: In the phantom study, the three differences in contrast medium concentration between vessel, stent, and background were obtained at 7x to 9x dilution. In clinical practice, however, the optimum contrast medium dilution concentration is higher than this because of the effect of blood flow. In the present study, three differences in vessel, stent, and background concentrations were obtained at 4x dilution.

Conclusion: The optimal contrast dilution concentration of 3D-RA for CASPER Rx was a 4-fold dilution concentration when the injection rate of the contrast medium was 3.5 mL/sec.