title: Whole-lung volume and density in spirometrically-gated inspiratory and expiratory CT in systemic sclerosis: correlation with static volumes at pulmonary function tests.
abstract: BACKGROUND
  Spiral low-dose computed tomography (LDCT) permits to measure whole-lung volume and density in a single breath-hold.
  
  
  OBJECTIVE
  To evaluate the agreement between static lung volumes measured with LDCT and pulmonary function test (PFT) and the correlation between the LDCT volumes and lung density in restrictive lung disease.
  
  
  METHODS
  Patients with Systemic Sclerosis (SSc) with (n = 24) and without (n = 16) pulmonary involvement on sequential thin-section CT and patients with chronic obstructive pulmonary disease (COPD)(n = 29) underwent spirometrically-gated LDCT at 90% and 10% of vital capacity to measure inspiratory and expiratory lung volumes and mean lung attenuation (MLA). Total lung capacity and residual volume were measured the same day of CT.
  
  
  RESULTS
  Inspiratory [95% limits of agreement (95% LoA)--43.8% and 39.2%] and expiratory (95% LoA -45.8% and 37.1%) lung volumes measured on LDCT and PFT showed poor agreement in SSc patients with pulmonary involvement, whereas they were in substantial agreement (inspiratory 95% LoA -14.1% and 16.1%; expiratory 95% LoA -13.5% and 23%) in SSc patients without pulmonary involvement and in inspiratory scans only (95% LoA -23.1% and 20.9%) of COPD patients. Inspiratory and expiratory LDCT volumes, MLA and their deltas differentiated both SSc patients with or without pulmonary involvement from COPD patients. LDCT lung volumes and density were not correlated in SSc patients with pulmonary involvement, whereas they did correlate in SSc without pulmonary involvement and in COPD patients.
  
  
  CONCLUSIONS
  In restrictive lung disease due to SSc there is poor agreement between static lung volumes measured using LDCT and PFT and the relationship between volume and density values on CT is altered.
authors.affiliation: Respiratory Medicine Unit, Department of Internal Medicine, University of Florence, Italy. gianna.camiciottoli@unifi.it
authors.forename: G
authors.initials: G
authors.lastname: Camiciottoli
authors.forename: S
authors.initials: S
authors.lastname: Diciotti
authors.forename: M
authors.initials: M
authors.lastname: Bartolucci
authors.forename: I
authors.initials: I
authors.lastname: Orlandi
authors.forename: F
authors.initials: F
authors.lastname: Bigazzi
authors.forename: M
authors.initials: M
authors.lastname: Matucci-Cerinic
authors.forename: M
authors.initials: M
authors.lastname: Pistolesi
authors.forename: M
authors.initials: M
authors.lastname: Mascalchi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D029424:Pulmonary Disease, Chronic Obstructive / Q000000981:diagnostic imaging; D012129:Respiratory Function Tests; D012595:Scleroderma, Systemic / Q000000981:diagnostic imaging*; D013147:Spirometry; D036542:Tomography, Spiral Computed / Q000379:methods*; D055815:Young Adult