Visualization of vessels for diagnostics and intervention are usually done under fluoroscopic X-ray view using intravenous contrast agents, which has potential risks. To avoid this problem an ultrasoundbased approach was investigated. The definition of reproducible geometric measures is important for image guided navigated implantations. Such measures can benefit from geometric body which approximate the vessels. We addressed the problem of fitting cylindric bodies to datasets by using a robust technique based on rejection strategies for irrelevant points and data sets.