320-detector CT imaging of the upper airway structure of patients with obstructive sleep apnea-hypopnea syndrome

Obstructive sleep apnea-hypopnea syndrome (OSAHS) is one of the most common sleep disorders that have significant associated health costs. It is caused by recurrent occlusion of the upper airway during sleep. Recently, many researchers have provided evidence that patients with OSAHS tend to have a large tongue, a comparatively prolonged soft palate, and a narrow upper airway.There are many therapeutic methods for OSAHS, although determining the obstructive points is very important. Several methods to study the morphology of the upper airway in patients with OSAHS are available: acoustic reflection, fluoroscopy, endoscopic observation, and computed tomography (CT). After our hospital took the lead in the introduction the first 320-detector CT in East China, our team studied the morphology of the upper airway in patients with OSAHS using this 320-detector CT.From July 2010 to July 2011, the upper airway of 66 patients with OSAHS and 22 control subjects were scanned using a 320-detector CT scanner at the time of deep inspiration, deep expiration, normal respiration, and Müller maneuver. Cross-sectional areas of the upper airway at the nasopharyngeal, velopharyngeal, and tongue-pharyngeal levels were measured and compared. Mean velopharyngeal cross-sectional areas in OSAHS were less than those in the control group at the time of deep inspiration, deep expiration, normal respiration, and Müller maneuver (P < 0.05). Mean tongue-pharyngeal cross-sectional areas in OSAHS were less than those in the control group at the time of deep inspiration and Müller maneuver (P < 0.05).The results showed that velopharyngeal and tongue-pharyngeal areas could be the main obstructive regions for OSAHS and that the 320-detector CT scanner would be of great utility in identifying the location of the upper airway obstruction in patients with OSAHS, in exploring the pathogenesis of OSAHS, and in designing the appropriate treatment plan and surgical positioning.