The CT assessment of normal adult upper airway

Objective: To measure the dimension of North Chinese upper airway on CT scan and to establish the diagnosis criterion of upper airway stricture. Methods: This study involved 225 normal adults without any apnea or snoring symptoms. The upper airways from roof of nasopharynx to glottis were evaluated by using Phlips Tomoscan AV Expander E1 spiral CT scanner. The areas and the dimensions of palate, uvula, lingua and epiglottis region were studied, and the thicknesses of retropharyngeal and lateral pharyngeal tissue were evaluated also. The normal extent of every variable was determined by unilateral 95% confidence interval. Results: The shapes of most upper airway across the section at different levels were transverse ellipse and the coronary diameter was larger than arrowy dimension. The ratio of testee who show longitudinal across section of upper airway at palate, uvula, lingua and epiglottis region were 3.11 %,10.67%,0.8% and 0% respectively. There was not obviously difference in most of variables among different age group. Besides of palate region,there was significant difference in most of variables between male and female. The normal extents of upper airway variables were established in male and female respectively. Conclusions:The CT assessment of normal adult upper airway can give an objective criterion to the diagnosis of upper airway stricture and the location of stricture site in OSAS patients. There are intrinsic anatomic factors which bring about more OSAS patients in male.