title: Neurochemical-structural changes evaluation of brain in patients with obstructive sleep apnea syndrome.
abstract: OBJECTIVE
  To evaluate neurochemical and structural changes in the patients with newly diagnosed obstructive sleep apnea syndrome (OSAS) by MR spectroscopy (MRS), T2 relaxometry, and diffusion weighted imaging (DWI).
  
  
  METHODS
  Following the acquisition of routine cranial MR, MRS, T2 relaxometry, and DWI images; spectroscopic metabolite ratios and DWI-T2 relaxometry findings of the thalami, hippocampi, frontal white matter (FWM) and frontal cortex of 24 OSAS patients and 9 controls were statistically compared. The relationship between two groups was evaluated with Mann-Whitney test.
  
  
  RESULTS
  Spectroscopic measurements in the frontal cortex and frontal white matter of the OSAS patients revealed significantly lower NAA/Cr ratios than those of the control group (P=0.004 and P=0.006, respectively). The measurements in the frontal white matter of the OSAS patients exhibited significantly lower NAA/Cho ratios compared with those of the control group (P=0.005). Thalamic Cho/Cr ratios of the patient group were significantly higher than those of the control group (P=0.002). In terms of the ADC-T2 relaxometry values, there was no significant relationship between the patient and the control groups (P>0.05).
  
  
  CONCLUSIONS
  MRS is a useful and non-invasive modality in showing neurochemical changes in various regions of the brain but our data does not show any change on diffusion weighting or T2 quantification in the OSAS group. DWI and T2 relaxometry appear to be not effective techniques to evaluate the brain structural changes of the patients with newly diagnosed OSAS.
authors.affiliation: Atatürk Training and Research Hospital, Department of Radiology, Bilkent, Ankara, Turkey. droktayalgin@gmail.com
authors.forename: Oktay
authors.initials: O
authors.lastname: Algin
authors.forename: Gokhan
authors.initials: G
authors.lastname: Gokalp
authors.forename: Gokhan
authors.initials: G
authors.lastname: Ocakoglu
authors.forename: Ahmet
authors.initials: A
authors.lastname: Ursavas
authors.forename: Ozlem
authors.initials: O
authors.lastname: Taskapilioglu
authors.forename: Bahattin
authors.initials: B
authors.lastname: Hakyemez
mesh_terms: D000328:Adult; D000368:Aged; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D001921:Brain / Q000378:metabolism* / Q000473:pathology*; D016022:Case-Control Studies; D002794:Choline / Q000378:metabolism*; D003401:Creatine / Q000378:metabolism*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D005625:Frontal Lobe / Q000378:metabolism / Q000473:pathology; D006624:Hippocampus / Q000378:metabolism / Q000473:pathology; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D020181:Sleep Apnea, Obstructive / Q000378:metabolism* / Q000473:pathology*; D018709:Statistics, Nonparametric; D013788:Thalamus / Q000378:metabolism / Q000473:pathology
chemical_list: D001224:Aspartic Acid; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline