[1] Univ Hosp Hamburg Eppendorf, Med Ctr, D-22046 Hamburg, Germany
[2] Univ Calif Los Angeles, David Geffen Sch Med, Dept Radiol, Los Angeles, CA USA
[3] Univ Hosp Essen, Dept Diagnost & Intervent Radiol & Neuroradiol, Essen, Germany
[4] Univ Hosp Essen, Dept Gastroenterol & Hepatol, Essen, Germany