1. University Hospital Bonn, Department of Radiology (J.A.L, A.F., H.L.G., A.M.S., C.M., D.T.), Bonn, Germany.
2. Department of Internal Medicine II (B.A.K., J.S., A.S., E.G., G.N., J.M.S.), Bonn, Germany.
3. Department of Medical Biometry, Informatics, and Epidemiology (R.F.), Bonn, Germany.
4. Department of Cardio-Thoracic Surgery (H.T.), Bonn, Germany.