Aortic stentgraft movement detection using digital roentgen stereophotogrammetric analysis on plane film radiographs -- initial results of a phantom study.

PURPOSE: To evaluate the feasibility of aortic stentgraft micromovement detection using digital roentgen stereophotogrammetric analysis on plane film radiographs. MATERIAL AND METHODS: An aortic stentgraft used for demonstration purposes was marked with 10 tantalum markers of 0.8 mm in diameter. The stentgraft was placed on a Plexiglas phantom with 5 tantalum markers of 1 mm in diameter simulating a fixed segment needed for mathematical analysis. In a subsequent step, the stentgraft was placed onto an orthopaedic spine model to simulate in vivo conditions.in a next step. Two radiographs taken simultaneously from different angles were used for simulating different stentgraft movement, e. g. translation, angulation, aortic pulsation and migration in the spine model. Movement of the stentgraft markers was analysed using a commercially available digital RSA setup (UmRSA(R) 4.1, RSA Biomedical, Umea, Sweden). RESULTS: Our study shows the feasibility of measuring aortic stentgraft movement and changes in stentgraft shape in the submillimeter range using digital roentgen stereophotogrammetric analysis. Translation along the 3 cardinal axes, change in stentgraft shape, simulation of aortic pulsation and simulation of in vivo conditions could be described precisely. CONCLUSION: Aortic stentgraft movement detection using digital roentgen stereophotogrammetric analysis on plane film radiographs is a very promising, precise method.