title: Defining normal upper airway motion in asymptomatic children during sleep by means of cine MR techniques.
abstract: OBJECTIVE
  To define normal upper airway motion in asymptomatic children during sleep by means of dynamic cine magnetic resonance (MR) techniques.
  
  
  METHODS
  In children referred for MR of the brain who required sedation, a sagittal midline cine MR sequence was performed. Motion of the nasopharynx, oropharynx, and hypopharynx was characterized as static patent, dynamic patent, intermittent collapse, or static collapsed; maximal diameter and greatest change in size were calculated in millimeters. Mouth position (open or closed) was determined. Parameters were compared with age (t test) and mouth position (Fisher exact test).
  
  
  RESULTS
  In the 148 subjects (mean age, 3.4 years), the nasopharynx showed dynamic motion in 53 (36%). The oropharynx was most commonly collapsed in 98 (66%) of the patients. The hypopharynx showed dynamic motion in 72 (49%) of the patients and was never collapsed. Vertical motion was present in 77 (52%) of the patients. The mouth was open in 96 (65%) of the patients. There was a statistically significant correlation between mouth position and dynamic motion in the oropharynx (P =.006) and in the nasopharynx (P <.006) but not in the hypopharynx (P =.655).
  
  
  CONCLUSIONS
  Dynamic changes in diameter were often seen in the nasopharynx and in the hypopharynx of asymptomatic sleeping children. However, collapse of the hypopharynx was not normally encountered.
authors.affiliation: Department of Radiology, Children's Hospital Medical Center, 3333 Burnet Ave, Cincinnati, OH 45229-3039, USA. lane.donnelly@chmcc.org
authors.forename: Lane F
authors.initials: LF
authors.lastname: Donnelly
authors.forename: Keith A
authors.initials: KA
authors.lastname: Casper
authors.forename: Bin
authors.initials: B
authors.lastname: Chen
authors.forename: Bernadette L
authors.initials: BL
authors.lastname: Koch
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D012143:Respiratory Physiological Phenomena; D012890:Sleep / Q000502:physiology*