1. Central Radiology Diagnostic Institute, Biometry and Epidemiology, University Hospital, Essen
2. Institute for Medical Information, Biometry and Epidemiology, University Hospital, Essen
3. Istitute for Radiological Diagnostics, Tübingen University, Tübingen
4. Clinic for Transplantation of Bone Marrow
5. Pneumology Center, The Ruhrland Clinic, University Hospital, Essen, Germany.