title: Pulmonary cysts identified on chest CT: are they part of aging change or of clinical significance?
abstract: OBJECTIVE
  To investigate the prevalence and natural course of pulmonary cysts in a population-based cohort and to describe the CT image characteristics in association with participant demographics and pulmonary functions.
  
  
  METHODS
  Chest CT scans of 2633 participants (mean age 59.2 years; 50% female) of the Framingham Heart Study (FHS) were visually evaluated for the presence of pulmonary cysts and their image characteristics. These findings were correlated with participant demographics and results of pulmonary function tests as well as the presence of emphysema independently detected on CT. The interval change was investigated by comparison with previous CT scans (median interval 6.1 years).
  
  
  RESULTS
  Pulmonary cysts were seen in 7.6% (95% CI 6.6% to 8.7%; 200/2633). They were not observed in participants younger than 40 years old, and the prevalence increased with age. Multiple cysts (at least five) were seen in 0.9% of all participants. Participants with pulmonary cysts showed significantly lower body mass index (BMI) (p<0.001). Pulmonary cysts were most likely to appear solitary in the peripheral area of the lower lobes and remain unchanged or slightly increase in size over time. Pulmonary cysts showed no significant influence on pulmonary functions (p=0.07-0.6) except for diffusing capacity of the lung for carbon monoxide (DLCO) (p=0.03) and no association with cigarette smoking (p=0.1-0.9) or emphysema (p=0.7).
  
  
  CONCLUSIONS
  Pulmonary cysts identified on chest CT may be a part of the aging changes of the lungs, occurring in asymptomatic individuals older than 40 years, and are associated with decreased BMI and DLCO. Multiple pulmonary cysts may need to be evaluated for the possibility of cystic lung diseases.
authors.affiliation: Department of Radiology, Center for Pulmonary Functional Imaging, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Araki
authors.affiliation: Department of Radiology, Center for Pulmonary Functional Imaging, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Mizuki
authors.initials: M
authors.lastname: Nishino
authors.affiliation: Department of Biostatistics, Boston University School of Public Health, Boston, Massachusetts, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Gao
authors.affiliation: Department of Biostatistics, Boston University School of Public Health, Boston, Massachusetts, USA The National Heart Lung and Blood Institute's Framingham Heart Study, Framingham, Massachusetts, USA.
authors.forename: Josée
authors.initials: J
authors.lastname: Dupuis
authors.affiliation: The Pulmonary and Critical Care Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Rachel K
authors.initials: RK
authors.lastname: Putman
authors.affiliation: The Pulmonary and Critical Care Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: George R
authors.initials: GR
authors.lastname: Washko
authors.affiliation: The Pulmonary and Critical Care Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Gary M
authors.initials: GM
authors.lastname: Hunninghake
authors.affiliation: The National Heart Lung and Blood Institute's Framingham Heart Study, Framingham, Massachusetts, USA Pulmonary Center and Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, USA.
authors.forename: George T
authors.initials: GT
authors.lastname: O'Connor
authors.affiliation: Department of Radiology, Center for Pulmonary Functional Imaging, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Hiroto
authors.initials: H
authors.lastname: Hatabu
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D058070:Asymptomatic Diseases; D003560:Cysts / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008171:Lung Diseases / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D012129:Respiratory Function Tests; D014057:Tomography, X-Ray Computed