Wall stress analysis of abdominal aortic aneurysms using 3D ultrasound

Wall stress analysis of abdominal aortic aneurysms is a novel tool that has proven high potential to improve risk stratification of abdominal aortic aneurysms (AAAs). Wall stress analysis is based on computed tomography (CT) and magnetic resonance imaging, however, 3D ultrasound (US) has not been used yet. In this study, the feasibility of 3D US based wall stress analysis is investigated and compared to CT. Three-dimensional US and CT data were acquired in 15 patients (diameter 35 - 90 mm). US data were segmented manually and compared to automatically acquired CT geometries by calculating the similarity index (SI) and Hausdorff distance (HD). Wall stresses were simulated at p = 140 mmHg using a non-linear material model (Raghavan & Vorp). The SI of US vs CT was 0.75 - 0.91, with a median HD of 5 - 15 mm, with the higher values found at the proximal and distal sides of the AAA. Wall stresses were in accordance with literature and a good agreement was found between US and CT-based median stresses and inter-quartile stresses. Stress values of US were typically higher, the result of geometrical irregularities, caused by the manual segmentation of the US data. In future work, an automated segmentation approach is the essential point of improvement.