MRI Analysis of Upper Airway in Patients with Obstructive Sleep Apnea-Hypopnea Syndrome

Background: To investigate the upper airway changes in obstructive sleep apnea-hypopnea syndrome (OSAHS) patients, we measured cross-sectional areas of the upper airway [retropalatine (RP) and restoglossal (RG) regions] and volumes of upper airway structures on upper airway MRI in OSAHS patients and normal controls. Methods: The Apnea/Hypopnea index (AHI) of OSAHS patients was calculated by overnight polysomnography whereas apnea-hypopnea screening for normal controls was performed by a portable screening device. Upper airway MR images were obtained in normal subjects and OSAHS patients using a 1.5-T MRI scanner. The following parameters were measured on MRI using Analyze 6.0 software: (1) mean area, minimal area, vertical and horizontal lengths of the minimal area in RP and RG region; (2) volumes of RP and RG airway, soft palate, lateral pharyngeal wall, lateral pharyngeal fat pad and tongue. Results: Nineteen OSAHS patients and 14 normal controls were included. Body mass index (BMI) and AHI were significantly higher in OSAS (BMI 27.7±2.5, AHI 56.8±22.3) than normal controls (BMI 23.0±1.9, AHI 3.5±2.1). OSAHS group had significantly smaller mean RP and RG area, smal lest area in RP and RG regions and horizontal length of smallest area in RP and RG regions. The volumes of soft palate and lateral pharyngeal wall were larger in the OSAHS group. Conclusions: Korean OSAHS patients had smaller mean RP and RG area, minimal RP and RG area and horizontal length in minimal RP and RG region and larger volume of soft palate and lateral pharyngeal wall than normal controls. J Korean Neurol Assoc 25(3):304-311, 2007