[1] Univ Helsinki, Dept Otorhinolaryngol, FI-00029 Helsinki, HUS, Finland
[2] Helsinki Univ Hosp, FI-00029 Helsinki, HUS, Finland
[3] Univ Helsinki, Dept Radiol, FI-00029 Helsinki, HUS, Finland
[4] Helsinki Univ Hosp, HUS Med Imaging Ctr, FI-00029 Helsinki, HUS, Finland
[5] Univ Helsinki, Dept Allergy, FI-00029 Helsinki, HUS, Finland