title: Sleep magnetic resonance imaging with electroencephalogram in obstructive sleep apnea syndrome.
abstract: OBJECTIVE
  To evaluate the mechanism and level of upper airway obstruction in obstructive sleep apnea (OSA) patients during natural sleep, together with synchronous electroencephalogram and respiratory events registration at 3-Tesla magnetic resonance imaging (MRI) platform with high spatial and temporal resolution.
  
  
  METHODS
  A prospective cohort study of 20 randomly selected OSA patients.
  
  
  METHODS
  Fifteen of 20 patients were able to complete spontaneous sleep during MRI. While asleep, dynamic MR images of pharynx were obtained in the midline sagittal view. During the scan, nasal and oral airflow, thoracoabdominal wall effort, and electroencephalogram were synchronously recorded. The physiologic data were retrospectively scored to identify periods of apneas and synchronized with dynamic MR images.
  
  
  RESULTS
  In all 15 patients, the site of complete airway obstruction occurred at the retropalatal space. We noticed different positions of the soft palate during apneic events. In seven of 15 patients (47%), the soft palate was attached to the tongue base and moved backward, compressing the airway. In five of 15 patients (33%), the soft palate was detached from the tongue base and solely moved backward, compressing the airway. In three patients (20%), we recorded both mechanisms of complete airway obstruction. In cases with attached soft palate to the tongue base, we noticed significant narrowing of the retrolingual space during apneic events.
  
  
  CONCLUSIONS
  We describe a novel mechanism of obstruction dependent on the position of soft palate. This mechanism might play an important role in selecting candidates for surgery or treatment with hypoglossal nerve stimulation.
  
  
  METHODS
  2b.
authors.affiliation: Clinical Radiology Institute, University Medical Centre Ljubljana, Ljubljana, Slovenia.
authors.forename: Pavel
authors.initials: P
authors.lastname: Kavcic
authors.affiliation: Clinical Radiology Institute, University Medical Centre Ljubljana, Ljubljana, Slovenia.
authors.forename: Ales
authors.initials: A
authors.lastname: Koren
authors.affiliation: Institute of Clinical Neurophysiology, Division of Neurology, University Medical Centre Ljubljana, Ljubljana, Slovenia.|Department of Neurology, Faculty of Medicine, University Medical Centre Ljubljana, Ljubljana, Slovenia.
authors.forename: Blaz
authors.initials: B
authors.lastname: Koritnik
authors.affiliation: Clinic of Otorhinolaryngology and Cervicofacial Surgery, University Medical Centre Ljubljana, Ljubljana, Slovenia.
authors.forename: Igor
authors.initials: I
authors.lastname: Fajdiga
authors.affiliation: Institute of Clinical Neurophysiology, Division of Neurology, University Medical Centre Ljubljana, Ljubljana, Slovenia.
authors.forename: Leja D
authors.initials: LD
authors.lastname: Groselj
mesh_terms: D000402:Airway Obstruction / Q000503:physiopathology; D004569:Electroencephalography; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D010160:Palate, Soft / Q000473:pathology*; D017286:Polysomnography; D020181:Sleep Apnea, Obstructive / Q000473:pathology* / Q000503:physiopathology*
keywords: Magnetic resonance imaging; hypoglossal nerve stimulation; obstructive sleep apnea; soft palate