Sleep magnetic resonance imaging as a new diagnostic method in obstructive sleep apnea syndrome.
OBJECTIVE
Although precise localization of obstruction sites in the upper airway during sleep is essential in subjects with obstructive sleep apnea syndrome (OSAS), no gold standard diagnostic method has been established. This study aimed to evaluate the dynamic collapse inside the upper airway by using cine magnetic resonance imaging (MRI), also called sleep MRI.


METHODS
Cross-sectional study with retrospective data.


METHODS
The changes in the transverse and anteroposterior diameters of the retrolingual airway were studied during a respiratory cycle in 35 snoring subjects. The collapsibility of the airway was calculated by using axial images, and the actual obstruction sites were also identified by using sagittal images.


RESULTS
Airway collapse occurred in the retropalatal area in 13 (37.1%) of 35 subjects and in both the retropalatal and retrolingual regions in 20 subjects (57.1%). The respiratory disturbance index (RDI) and supine RDI were higher and the minimal oxygen saturation during sleep (MinSaO₂) value was lower in subjects with both retropalatal and retrolingual obstruction than in those with only retropalatal obstruction. Airway collapse analyzed by using axial images was classified into four subgroups: patent group (five of 35, 14.2%), anteroposterior collapse group (one of 35, 2.9%), transverse collapse group (14 of 35, 40%) and circumferential collapse group (15 of 35, 42.9%). Supine RDI, MinSaO₂, and age were significantly different between these four groups. In addition, anteroposterior, transverse, and circumferential collapses correlated well with MinSaO₂. Significant correlation was also found between RDI/supine RDI and transverse collapse.


CONCLUSIONS
Sleep MRI is a valuable method for evaluating dynamic obstruction during sleep and may be helpful in selecting the appropriate treatment approaches.
Department of Otorhinolaryngology, Seoul National University College of Medicine, Seoul, South Korea.
Il Joon
IJ
Moon
Doo Hee
DH
Han
Jeong-Whun
JW
Kim
Chae-Seo
CS
Rhee
Myung-Whun
MW
Sung
Jong-Wan
JW
Park
Dong Sung
DS
Kim
Chul Hee
CH
Lee
D003430:Cross-Sectional Studies; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012890:Sleep; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis* / Q000503:physiopathology; D016683:Supine Position