[1] SINTEF Technol & Soc, Dept Hlth Res, NO-7465 Trondheim, Norway
[2] Norwegian Univ Sci & Technol, Dept Biol, N-7034 Trondheim, Norway
[3] St Olavs Hosp, Dept Lung Med, Trondheim, Norway
[4] Norwegian Univ Sci & Technol, Fac Med, Dept Circulat & Med Imaging, N-7034 Trondheim, Norway