title: Evaluation of water content around airway in obstructive sleep apnea patients using peripharyngeal mucosal T2 magnetic resonance imaging.
abstract: BACKGROUND
  Obstructive sleep apnea (OSA) is common sleep disorder characterized by repetitive episodes of airway closure which usually occurs in the retropalatal region of the oropharynx. It has been known that upper airway mucosa in OSA patients is described as edematous, but not fully clarified.
  
  
  OBJECTIVE
  This study aimed to investigate and establish magnetic resonance imaging (MRI) parameter to estimate tissue water content at retropalatal level and its relationship with sleep parameters in OSA patients.
  
  
  METHODS
  Forty-eight subjects with OSA underwent overnight polysomnography and cervical MRI with 1.5-tesla [mean (SD) age 55 (14) years and apnea-hypopnea index (AHI) 45.2 (26.1) events/hour, 79.2% male]. On the axial T2-weighted images from epipharynx to oropharynx, the signal intensities of masseter muscle and peripharyngeal mucosa [T2 mucous-to-masseter intensity ratio (T2MMIR)], was used as water content estimation in the retropalatal region. Partial correlation analysis was performed to examine the correlation between T2MMIR and polysomnography parameters.
  
  
  RESULTS
  We found that there were strong and positive correlations between the T2MMIR and AHI (r = 0.545, P < 0.05), supine AHI (r = 0.553, P < 0.05) and REM AHI (r = 0.640, P < 0.01) by partial correlation analysis. Besides, in patients with less efficient sleep who had more stage 1 sleep, significantly higher T2MMIR was noted (r = 0.357, P < 0.05).
  
  
  CONCLUSIONS
  This study confirmed that peripharyngeal T2MMIR can be a simple parameter representing peripharyngeal tissue water contents related to severe OSA.
authors.affiliation: Department of Cardiovascular Medicine, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan.
authors.forename: Anita
authors.initials: A
authors.lastname: Rahmawati
authors.affiliation: Department of Health Sciences, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Chishaki
authors.affiliation: Kirameki Project Carrier Support Center, Kyushu University Hospital, Fukuoka, Japan.|Sleep Apnea Center, Kyushu University Hospital, Fukuoka, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Ohkusa
authors.affiliation: Sleep Apnea Center, Kyushu University Hospital, Fukuoka, Japan.
authors.forename: Sonomi
authors.initials: S
authors.lastname: Hashimoto
authors.affiliation: Department of Otorhinolaryngology, Kyushu University Graduate School of Medical Sciences, Fukuoka Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Adachi
authors.affiliation: Department of Molecular Imaging and Diagnosis, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan.
authors.forename: Michinobu
authors.initials: M
authors.lastname: Nagao
authors.affiliation: Department of Cardiovascular Medicine, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan.|Sleep Apnea Center, Kyushu University Hospital, Fukuoka, Japan.
authors.forename: Mari
authors.initials: M
authors.lastname: Konishi Nishizaka
authors.affiliation: Sleep Apnea Center, Kyushu University Hospital, Fukuoka, Japan.
authors.forename: Shin-Ichi
authors.initials: SI
authors.lastname: Ando
mesh_terms: D000328:Adult; D000368:Aged; D015992:Body Mass Index; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009061:Mouth Mucosa / Q000000981:diagnostic imaging* / Q000503:physiopathology; D009960:Oropharynx / Q000000981:diagnostic imaging* / Q000503:physiopathology; D017286:Polysomnography / Q000379:methods; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000150:complications / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology; D055105:Waist Circumference; D014867:Water / Q000502:physiology
chemical_list: D014867:Water
keywords: magnetic resonance imaging - obstructive sleep apnea - pharynx - T2-weighted image