title: Dynamic 3-D MR Visualization and Detection of Upper Airway Obstruction During Sleep Using Region-Growing Segmentation.
abstract: OBJECTIVE
  We demonstrate a novel and robust approach for visualization of upper airway dynamics and detection of obstructive events from dynamic 3-D magnetic resonance imaging (MRI) scans of the pharyngeal airway.
  
  
  METHODS
  This approach uses 3-D region growing, where the operator selects a region of interest that includes the pharyngeal airway, places two seeds in the patent airway, and determines a threshold for the first frame.
  
  
  RESULTS
  This approach required 5 s/frame of CPU time compared to 10 min/frame of operator time for manual segmentation. It compared well with manual segmentation, resulting in Dice Coefficients of 0.84 to 0.94, whereas the Dice Coefficients for two manual segmentations by the same observer were 0.89 to 0.97. It was also able to automatically detect 83% of collapse events.
  
  
  CONCLUSIONS
  Use of this simple semiautomated segmentation approach improves the workflow of novel dynamic MRI studies of the pharyngeal airway and enables visualization and detection of obstructive events.
  
  
  CONCLUSIONS
  Obstructive sleep apnea (OSA) is a significant public health issue affecting 4-9% of adults and 2% of children. Recently, 3-D dynamic MRI of the upper airway has been demonstrated during natural sleep, with sufficient spatiotemporal resolution to noninvasively study patterns of airway obstruction in young adults with OSA. This study makes it practical to analyze these long scans and visualize important factors in an MRI sleep study, such as the time, site, and extent of airway collapse.
authors.forename: Ahsan
authors.initials: A
authors.lastname: Javed
authors.forename: Yoon-Chul
authors.initials: YC
authors.lastname: Kim
authors.forename: Michael C K
authors.initials: MC
authors.lastname: Khoo
authors.forename: Sally L Davidson
authors.initials: SL
authors.lastname: Ward
authors.forename: Krishna S
authors.initials: KS
authors.lastname: Nayak
mesh_terms: D000293:Adolescent; D000328:Adult; D000465:Algorithms; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D012137:Respiratory System / Q000503:physiopathology; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis* / Q000503:physiopathology; D055815:Young Adult