["To study the sensitivity, specificity and clinical value of coranal CT scan of trachea and bronchus in diagnoing children's foreign body in bronchus.", '30 cases of the children with foreign body in their trachea and bronchus were examined by chest X ray (chest X-ray), and by coranal CT scan at the same time. (some of them were compared with axial CT scan.)', 'The position of foreign body in trachea and bronchus was definitely diagnosed by coronal CT scan in all cases, of whom, 28 cases with obstructive emphysema; 5 case with obstructive pneumonia and 3 cases with obstructive atelectasis.'] Do [ Diagnosis of foreign bodies in trachea and bronchus of children by means of coronal CT scan ]?