[1] Ludwig Maximilians Univ Hosp, Inst Clin Radiol, Nussbaumstr 20, D-80336 Munich, Germany
[2] Univ Hosp Heidelberg, Diagnost & Intervent Radiol, Heidelberg, Germany
[3] Univ Hosp Birmingham, Dept Radiol, Birmingham B15 2TH, W Midlands, England
[4] Ludwig Maximilians Univ Munchen, Dr von Hauner Childrens Hosp, Dept Rheumatol & Immunol, Munich, Germany