title: Assessment by airway ellipticity on cine-MRI to differentiate severe obstructive sleep apnea.
abstract: BACKGROUND
  The severity of obstructive sleep apnea (OSA) is assessed by the apnea-hypopnea index (AHI) determined from polysomnography (PSG). However, PSG requires a specialized facility with well-trained specialists and takes overnight. Therefore, simple tools, which could distinguish severe OSA, have been needed before performing PSG.
  
  
  OBJECTIVE
  We propose the new index using cine-MRI as a screening test to differentiate severe OSA patients, who would need PSG and proper treatment.
  
  
  METHODS
  Thirty-six patients with suspected OSA (mean age 54.6 y, mean AHI 52.6 events/h, 33 males) underwent airway cine-MRI at the fourth cervical vertebra level during 30 s of free breathing and PSG. The minimum airway ellipticity (AE) in 30 s duration was measured, and was defined as the severity of OSA. Patients were divided into severe OSA, not-severe OSA, and normal groups, according to PSG results. The comparison of AE between any two of the three groups was performed by Wilcoxon rank-sum test. Receiver operating characteristic (ROC) curve analysis was performed to determine the optimal cut-off of AE for identifying severe OSA patients.
  
  
  RESULTS
  The minimum AE for severe OSA was significantly lower than that for not-severe OSA and normal (severe, 0.17 ± 0.16; not severe, 0.31 ± 0.17; normal, 0.38 ± 0.19, P < .05). ROC analysis revealed that the optimal cutoff of the minimum AE 0.21 identified severe OSA patients, with an area under the curve of 0.75, 68% sensitivity, and 83% specificity.
  
  
  CONCLUSIONS
  AE is a feasible quantitative index, and a promising screening test for detecting severe OSA patients.
authors.affiliation: Division of Radiology, Department of Medical Technology, Kyushu University Hospital, Fukuoka, Japan.
authors.forename: Tsukasa
authors.identifier: http://orcid.org/0000-0002-9673-2147
authors.initials: T
authors.lastname: Kojima
authors.affiliation: Department of Radiological Technology, Faculty of Fukuoka Medical Technology, Teikyo University, Fukuoka, Japan.
authors.forename: Masateru
authors.initials: M
authors.lastname: Kawakubo
authors.affiliation: Sleep Apnea Center, Kyushu University Hospital, Fukuoka, Japan.|Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Mari K
authors.initials: MK
authors.lastname: Nishizaka
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Anita
authors.initials: A
authors.lastname: Rahmawati
authors.affiliation: Sleep Apnea Center, Kyushu University Hospital, Fukuoka, Japan.
authors.forename: Shin-Ichi
authors.initials: SI
authors.lastname: Ando
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Chishaki
authors.affiliation: Division of Radiology, Department of Medical Technology, Kyushu University Hospital, Fukuoka, Japan.
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Nakamura
authors.affiliation: Department of Diagnostic Imaging and Nuclear medicine, Tokyo Women's Medical University, Tokyo, Japan.
authors.forename: Michinobu
authors.initials: M
authors.lastname: Nagao
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D056151:Airway Remodeling / Q000502:physiology*; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008403:Mass Screening / Q000379:methods; D008875:Middle Aged; D017286:Polysomnography / Q000379:methods; D012119:Respiration; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis* / Q000503:physiopathology; D055815:Young Adult
keywords: magnetic resonance imaging; obstructive sleep apnea; polysomnography; severity of illness index