title: Non-Gaussian Diffusion Imaging Shows Brain Myelin and Axonal Changes in Obstructive Sleep Apnea.
abstract: OBJECTIVE
  Obstructive sleep apnea (OSA) is accompanied by brain changes in areas that regulate autonomic, cognitive, and mood functions, which were initially examined by Gaussian-based diffusion tensor imaging measures, but can be better assessed with non-Gaussian measures. We aimed to evaluate axonal and myelin changes in OSA using axial (AK) and radial kurtosis (RK) measures.
  
  
  METHODS
  We acquired diffusion kurtosis imaging data from 22 OSA and 26 controls; AK and RK maps were calculated, normalized, smoothed, and compared between groups using analysis of covariance.
  
  
  RESULTS
  Increased AK, indicating axonal changes, emerged in the insula, hippocampus, amygdala, dorsolateral pons, and cerebellar peduncles and showed more axonal injury over previously identified damage. Higher RK, showing myelin changes, appeared in the hippocampus, amygdala, temporal and frontal lobes, insula, midline pons, and cerebellar peduncles and showed more widespread myelin damage over previously identified injury.
  
  
  CONCLUSIONS
  Axial kurtosis and RK measures showed widespread changes over Gaussian-based techniques, suggesting a more sensitive nature of kurtoses to injury.
authors: From the *Department of Anesthesiology; †UCLA School of Nursing; Departments of ‡Medicine, §Pulmonary Medicine and Critical Care, and ∥Neurobiology; ¶Brain Research Institute; and Departments of #Radiological Sciences and **Bioengineering, University of California at Los Angeles, Los Angeles, CA.
authors: Sudhakar
authors: S
authors: Tummala
authors: Bhaswati
authors: B
authors: Roy
authors: Ruchi
authors: R
authors: Vig
authors: Bumhee
authors: B
authors: Park
authors: Daniel W
authors: DW
authors: Kang
authors: Mary A
authors: MA
authors: Woo
authors: Ravi
authors: R
authors: Aysola
authors: Ronald M
authors: RM
authors: Harper
authors: Rajesh
authors: R
authors: Kumar
mesh_terms: D001369:Axons; D001921:Brain / Q000000981:diagnostic imaging / Q000503:physiopathology; D001931:Brain Mapping / Q000379:methods; D003430:Cross-Sectional Studies; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D009186:Myelin Sheath; D015203:Reproducibility of Results; D020181:Sleep Apnea, Obstructive / Q000000981:diagnostic imaging* / Q000503:physiopathology