[1] Univ Munich, Univ Hosp Munich, Inst Clin Radiol, D-81377 Munich, Germany
[2] Univ Hosp Essen, Dept Diagnost & Intervent Radiol & Neuroradiol, D-45122 Essen, Germany
[3] Univ Munster, Dept Clin Radiol, Munster, Germany
[4] Klinikum Osnabruck Rontgen & Strahlenklin, Osnabruck, Germany
[5] Univ Heidelberg, Med Fac Mannheim, Univ Hosp Mannheim, Dept Clin Radiol & Nucl Med, D-68167 Mannheim, Germany