[1] Univ Klinikum Regensburg, Inst Rontgendiagnost, D-93042 Regensburg, Germany
[2] Univ Klinikum Regensburg, Klin & Poliklin Innere Med 2, D-93042 Regensburg, Germany
[3] Univ N Carolina, Dept Internal Med, Div Gastroenterol & Hepatol, Chapel Hill, NC USA