title: Brain diffusion changes in obstructive sleep apnoea syndrome.
abstract: BACKGROUND
  Obstructive sleep apnoea syndrome (OSAS) is a disorder characterized by repeated apnoeic episodes during sleep. Neurocognitive changes secondary to OSAS are likely to occur due to hypoxia in certain brain locations. Advances in magnetic resonance imaging technology, such as diffusion-weighted imaging (DWI), enable non-invasive and accurate identification of OSAS-induced changes.
  
  
  OBJECTIVE
  We aimed to use DWI to investigate changes in the brain secondary to hypoxia in OSAS.
  
  
  METHODS
  Eighty-eight patients underwent polysomnography and were classified as non-OSAS, mild-moderate OSAS and severe OSAS sufferers. DWI was used to evaluate 14 areas of the brain, and apparent diffusion coefficients (ADCs) were calculated. We investigated whether there were differences in the ADC values in specific areas of the brain between the non-OSAS and OSAS patients.
  
  
  RESULTS
  We measured the ADC values of the 68 newly diagnosed OSAS patients (21 mild, 15 moderate and 32 severe) and of 20 healthy controls. There were significant increases in the ADC values in the hippocampus, amygdala and putamen in OSAS patients. Compared to the non-OSAS subjects, the ADC values of the putamen in severe OSAS patients, those of the hippocampus in moderate or severe OSAS patients and those of the amygdala in moderate OSAS patients were significantly increased. A negative correlation between the lowest oxygen saturation during sleep and the ADC values of the hippocampus and amygdala was found.
  
  
  CONCLUSIONS
  Increased ADC levels in the hippocampus, amygdala and putamen in OSAS patients indicate hypoxia and likely cause vasogenic oedema in specific regions of the brain.
authors.affiliation: Department of Pulmonology, Bezmialem Vakif University, Fatih, Turkey.
authors.forename: Muhammed
authors.initials: M
authors.lastname: Emin Akkoyunlu
authors.forename: Levent
authors.initials: L
authors.lastname: Kart
authors.forename: Rukiye
authors.initials: R
authors.lastname: Kılıçarslan
authors.forename: Mehmet
authors.initials: M
authors.lastname: Bayram
authors.forename: Ayşe
authors.initials: A
authors.lastname: Aralasmak
authors.forename: Rasul
authors.initials: R
authors.lastname: Sharifov
authors.forename: Alpay
authors.initials: A
authors.lastname: Alkan
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D002560:Cerebrovascular Circulation; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology*