[1] Univ Trondheim Hosp, St Olavs Hosp, Dept Surg, N-7006 Trondheim, Norway
[2] Norwegian Univ Sci & Technol, Fac Med, Dept Circulat & Med Imaging, N-7006 Trondheim, Norway
[3] Norwegian Univ Sci & Technol, Dept Publ Hlth & Gen Practice, Fac Med, N-7006 Trondheim, Norway