title: Paratracheal air cysts: prevalence and relevance to pulmonary emphysema and bronchiectasis using thoracic multidetector CT.
abstract: OBJECTIVE
  We aimed to determine the prevalence of paratracheal air cysts (PTACs) and the relationship of PTACs with emphysema and bronchiectasis through retrospective analysis of multidetector computed tomography (MDCT) findings.
  
  
  METHODS
  MDCT findings of 1027 consecutive patients who underwent routine thorax examination between January 2012 and January 2013 were evaluated retrospectively for the presence of PTACs. Localization of the PTACs, as well as their size, shape, and relationship with the trachea were examined. Presence of emphysema and bronchiectasis was recorded, and bronchiectasis severity index was calculated when present. We randomly selected 80 patients who had no visible PTACs as the control group. The findings of patients with and without PTACs were compared.
  
  
  RESULTS
  PTACs were determined in 82 of 1027 patients (8%), in 8.8% of females and 7.3% of males. The presence of PTACs was determined to be independent of gender (P = 0.361). Eighty-one PTACs (98.8%) were located in the right side of the trachea and 56.1% had a tracheal connection. The presence of PTACs significantly correlated with the presence and severity of bronchiectasis (P = 0.001 and P = 0.005 respectively). There was no significant relationship between the presence of PTACs and the presence of emphysema on CT images (P = 0.125).
  
  
  CONCLUSIONS
  The prevalence of PTACs was determined as 8% in this study. There was significant association between PTACs and bronchiectasis.
authors.affiliation: Department of Radiology, Harran University Medical School, Şanlıurfa, Turkey. drnurefsan@yahoo.com.
authors.forename: Nurefsan
authors.initials: N
authors.lastname: Boyaci
authors.forename: Dilek
authors.initials: D
authors.lastname: Sen Dokumaci
authors.forename: Ekrem
authors.initials: E
authors.lastname: Karakas
authors.forename: Funda
authors.initials: F
authors.lastname: Yalcin
authors.forename: Ayse Gul
authors.initials: AG
authors.lastname: Oney Kurnaz
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001987:Bronchiectasis / Q000000981:diagnostic imaging / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008476:Mediastinal Cyst / Q000000981:diagnostic imaging / Q000453:epidemiology*; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods; D015995:Prevalence; D011656:Pulmonary Emphysema / Q000000981:diagnostic imaging / Q000453:epidemiology*; D012189:Retrospective Studies; D014421:Turkey / Q000453:epidemiology; D055815:Young Adult