Accurate Detection of Stent-Graft Migration in a Pulsatile Aortic Model Using Roentgen Stereophotogrammetric Analysis

Purpose: To evaluate the feasibility and accuracy of Roentgen stereophotogrammetric analy-sis (RSA) versus computed tomography (CT) for detecting stent-graft migration in an in vitro pulsatile circulation model and to study the feasibility of a nitinol endovascular clip (NEC) as an aortic wall reference marker for RSA. Methods: An aortic model with stent-graft was constructed and connected to an artificial circulation with a physiological flow and pressure profile. Tantalum markers and NECs were used as aortic reference markers for RSA analysis. Stent-graft migrations were measured during pulsatile circulation with RSA and CT. CT images acquired with 64×0.5-mm beam collimation were analyzed with Vitrea postprocessing software using a standard clinical protocol and central lumen line reconstruction. RSA in the model with the circulation switched off was used as the reference standard to determine stent-graft migration. The measurement errors of RSA and CT were determined during pulsatile circulation. Results: The mean measurement error ± standard deviation (maximum) of RSA during pulsa-tile circulation using the tantalum markers was –0.5±0.16 (0.7) mm. Using the NEC, the mean (maximum) measurement error was –0.4±0.25 (1.1) mm. The mean (maximum) measurement error of CT was –1.1±1.17 (2.8) mm. Conclusion: RSA is an accurate and feasible tool to measure stent-graft migration in a pulsatile environment. Migration measurement with RSA was more accurate than CT in this experimen-tal setup. The nitinol clip tested in this study is potentially feasible as an aortic reference marker in patients after endovascular repair. I RSA for S-