[1] Univ Amsterdam, Acad Med Ctr, Dept Radiol, NL-1105 AZ Amsterdam, Netherlands
[2] Univ Amsterdam, Acad Med Ctr, Dept Social Med, NL-1105 AZ Amsterdam, Netherlands
[3] Univ Amsterdam, Acad Med Ctr, Dept Clin Epidemiol & Biostat, NL-1105 AZ Amsterdam, Netherlands
[4] Univ Hosp Maastricht, Dept Surg, NL-6229 HX Maastricht, Netherlands
[5] Univ Med Ctr Utrecht, Dept Surg, NL-3584 CX Utrecht, Netherlands
[6] Univ Amsterdam, Acad Med Ctr, Dept Gastroenterol, NL-1105 AZ Amsterdam, Netherlands
[7] Zaans Med Ctr, Dept Surg, NL-1502 DV Zaandam, Netherlands
[8] Vrije Univ Amsterdam Med Ctr, Dept Gastroenterol, NL-1081 HV Amsterdam, Netherlands
[9] Univ Amsterdam, Acad Med Ctr, Dept Surg, NL-1105 AZ Amsterdam, Netherlands
[10] Onze Lieve Vrouw Hosp, Dept Surg, NL-1091 AC Amsterdam, Netherlands