Prediction of aortoiliac stent-graft length: Comparison of measurement methods

PURPOSE: To determine the accuracy of helical computed tomography (CT), pro jectional angiography derived from CT angiography, and intravascular ultras onographic withdrawal (IUW) length measurements for predicting appropriate aortoiliac stent-graft length. MATERIALS AND METHODS: Helical CT data from 33 patients were analyzed befor e and after endovascular repair of abdominal aortic aneurysm (Aneuryx graft , n = 31; Excluder graft, n = 2). The aortoiliac length of the median lumin al centerline (MLC) and the shortest path (SP) that remained at least one c ommon iliac arterial radius away from the vessel wall were calculated. Conv entional angiographic measurements were Simulated from CT data as the lengt h of the three-dimensional MLC projected onto four standard viewing planes. These predeployment lengths and IUW length, available in 24 patients, were compared with the aortoiliac arterial length after stent-graft deployment. RESULTS: The mean error values of SP, MLC, the maximum projected MLC, and I UW were -2.1 mm +/- 4.6 (SD) (P = .013), 9.8 mm +/- 6.8 (P < .001), -5.2 mm +/- 7.8 (P < .001), and -14.1 mm +/- 9.3 (P < .001), respectively. The pre procedural prediction of the postprocedural aortoiliac length with the SP w as significantly more accurate than that with the MLC (P < .001), maximum p rojected MLC (P < .001), and IUW (P < .001). CONCLUSION: The shortest aortoiliac path length maintaining at least one ra dius distance from the vessel wall most accurately enabled stent-graft leng th prediction for 31 AneuRx and two Excluder stent-grafts.