Abstract. We introduce a novel model-based approach for the segmentation and quantification of the aortic arch morphology in 3D CTA images for endovascular aortic repair. The approach is based on a 3D analytic intensity model for thick vessels, which is directly fitted to the image. Based on the fitting results we compute the (local) 3D vessel curvature and torsion as well as the relevant lengths not only along the 3D centerline but particularly along the inner and outer contour. These measurements are important for pre-operative planning. We have successfully applied our approach using 3D CTA images and have compared the results with ground truth obtained by a radiologist. It turned out that our approach yields accurate estimation results.