title: Changes in volume-corrected whole-lung density in smokers and former smokers during the ITALUNG screening trial.
abstract: OBJECTIVE
  To evaluate with a volume-corrected whole-lung approach changes in lung density over 2 years consistent with progression of pulmonary emphysema in smokers and former smokers enrolled in the ITALUNG trial of lung cancer screening using low-dose computed tomography (LDCT).
  
  
  METHODS
  A total of 103 subjects (mean age 63±4 y with a pack-year history of at least 20) underwent 2 whole-lung LDCT examinations 2 years apart. Visual assessment was made independently by 2 experienced observers on the initial LDCT examination with a 0 to 4 grading system for each of 6 regions (right and left upper, mid, and lower lung). The whole-lung 15th percentile of attenuation coefficient and relative area (RA) at -910 HU, both corrected to the individual lung volume (Perc15v and RA910v), were measured on the 2 LDCT examinations. The intrasubject variability of Perc15v and RA910v was previously determined in 32 other subjects of the trial examined using the same scanner and technique twice over a 3-month interval for suspicious nodules.
  
  
  RESULTS
  The 2 operators agreed on the presence of mild to severe emphysema (visual score ≥1 in at least 1 region) at initial LDCT examination in 24 (23%) of the 103 subjects. Fifteen subjects (15%) showed a Perc15v change between the 2 examinations exceeding the lower 95% limit of agreement, indicating progression of emphysema with a mean difference in lung density of -14.7%±2.6%. Ten of the 15 were identified as showing emphysema progression by RA910v as well. No association was observed between progression of emphysema and visual evidence of emphysema at initial LDCT examination, smoking status, or pack-years at baseline, or intervening changes in smoking habits.
  
  
  CONCLUSIONS
  Once variations in inspiratory lung volumes are taken into account, changes in lung density over 2 years consistent with progression of pulmonary emphysema in elderly smokers and former smokers are uncommon.
authors.affiliation: Sezione di Radiodiagnostica, Dipartimento di Fisiopatologia Clinica, Università di Firenze, Viale Morgagni 85, Florence, Italy. m.mascalchi@dfc.unifi.it
authors.forename: Mario
authors.initials: M
authors.lastname: Mascalchi
authors.forename: Nicola
authors.initials: N
authors.lastname: Sverzellati
authors.forename: Massimo
authors.initials: M
authors.lastname: Falchini
authors.forename: Giuditta
authors.initials: G
authors.lastname: Favilli
authors.forename: Simone
authors.initials: S
authors.lastname: Lombardo
authors.forename: Letizia
authors.initials: L
authors.lastname: Macconi
authors.forename: Eugenio
authors.initials: E
authors.lastname: Paci
authors.forename: Andrea Lopes
authors.initials: AL
authors.lastname: Pegna
authors.forename: Fabio
authors.initials: F
authors.lastname: Falaschi
authors.forename: Maurizio
authors.initials: M
authors.lastname: Zompatori
authors.forename: Stefano
authors.initials: S
authors.lastname: Diciotti
mesh_terms: D000368:Aged; D003720:Densitometry; D018450:Disease Progression; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008168:Lung / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D015588:Observer Variation; D009929:Organ Size; D011656:Pulmonary Emphysema / Q000000981:diagnostic imaging*; D011829:Radiation Dosage; D012907:Smoking