mehrzad bahtouee department of internal medicine (division of pulmonary), bushehr medical center hospital, bushehr university of medical sciences, bushehr, iran jamshid saberifard department of radiology, bushehr medical center hospital, bushehr university of medical sciences, bushehr, iran hamid javadi research center of gastroenterology and hepatology (grcgh), golestan university of medical sciences, gorgan, iran iraj nabipour the persian gulf tropical medicine research center, bushehr university of medical sciences, bushehr, iran hasan malakizadeh department of internal medicine (division of pulmonary), bushehr medical center hospital, bushehr university of medical sciences, bushehr, iran gholamhossein monavvarsadegh department of internal medicine (division of pulmonary), bushehr medical center hospital, bushehr university of medical sciences, bushehr, iran