title: The progression of thyroid cartilage calcification as it relates to the utilization of laryngeal ultrasound.
abstract: OBJECTIVE
  The purpose of this study is to review the computed tomography (CT) scans of infants, children, and adults to assess the degree of calcification of the thyroid cartilage at various ages in order to understand in which age group laryngeal ultrasound can be utilized.
  
  
  METHODS
  Retrospective.
  
  
  METHODS
  Two hundred patients from newborn to 50 years who received a CT scan of the neck were identified. The Hounsfield units (HU) of the thyroid cartilage were calculated at one o'clock, four o'clock, eight o'clock, and eleven o'clock at the level of the true and false vocal fold. The Spearman correlation coefficient was calculated to evaluate the correlation between each measure and age, then a linear regression with a logarithmic transformation was applied to further study how the measures were related to age.
  
  
  RESULTS
  The Spearman correlation coefficients ranged from 0.58 to 0.75. The P values of these coefficients were all < 0.0001, showing a significant relationship to age. The age increase by 1 year resulted in increased calcification by 1.5% to 4%. The Wilcoxon signed rank test compared the rate of calcification at each site measured. This showed that the two posterolateral sites calcify faster than the two anteromedial sites.
  
  
  CONCLUSIONS
  The thyroid cartilage calcifies at a rate that is significantly related to increasing age and calcifies in a posterolateral to anteromedial direction. Based on the HU, the thyroid cartilage is not consistently denser than soft tissue until greater than 40 years of age, which would make laryngeal ultrasound feasible for this population.
  
  
  METHODS
  4.
authors.affiliation: Bobby R. Alford Department of Otolaryngology-Head and Neck Surgery, Baylor College of Medicine, Texas Children's Hospital Houston, Texas, U.S.A.
authors.forename: Ashley E
authors.initials: AE
authors.lastname: Wenaas
authors.affiliation: Department of Radiology, Texas Children's Hospital Houston, Texas, U.S.A.
authors.forename: Brandon
authors.initials: B
authors.lastname: Tran
authors.affiliation: Bobby R. Alford Department of Otolaryngology-Head and Neck Surgery, Baylor College of Medicine, Texas Children's Hospital Houston, Texas, U.S.A.|Department of Otolaryngology-Head and Neck Surgery, Texas Children's Hospital Houston, Texas, U.S.A.
authors.forename: Julina
authors.initials: J
authors.lastname: Ongkasuwan
mesh_terms: D000293:Adolescent; D000328:Adult; D002114:Calcinosis / Q000000981:diagnostic imaging* / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D018450:Disease Progression; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007830:Larynx / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013957:Thyroid Cartilage / Q000000981:diagnostic imaging* / Q000473:pathology; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography
keywords: Thyroid cartilage calcification; laryngeal ultrasound