title: Assessment of emphysema in COPD: a functional and radiologic study.
abstract: OBJECTIVE
  A combination of functional measurements reflecting a decrease in maximum flow, a degree of lung hyperinflation, the relationship between maximum inspiratory and expiratory flows, bronchodilator response, and diffusing capacity of the lung for carbon monoxide (DLCO) was used to quantify the extent of emphysema, as assessed by high-resolution CT (HRCT) scanning.
  
  
  METHODS
  Forced inspiratory and expiratory spirometry, lung volumes, reversibility test, and single-breath diffusing capacity were assessed before and after inhaling albuterol, 200 microg. Relationships between lung function variables and emphysema extent, as determined by HRCT scanning, were tested by univariate and multivariate analyses.
  
  
  METHODS
  Thirty-nine COPD outpatients with moderate-to-severe obstruction.
  
  
  RESULTS
  Emphysema extent, as assessed by HRCT scanning, ranged from 18 to 70%. All of the lung function parameters that were studied, except for the change in FEV1 percent predicted after salbutamol inhalation, correlated significantly with the extent of emphysema (r2 range, 0.19 to 0.44). Functional residual capacity, forced expiratory flow at 50% of FVC/forced inspiratory flow at 50% of FVC, DLCO/alveolar volume ratio, and bronchodilator-induced change in FEV1/FVC ratio were the only variables retained by stepwise multiple regression analysis. The multiple regression model explained 71% of the variability of emphysema extent measured by HRCT scanning.
  
  
  CONCLUSIONS
  The combination of lung function measurements reflecting lung hyperinflation, bronchial collapsibility, lung diffusing capacity, and bronchodilator response provides a good estimate of the extent of emphysema, as evaluated by HRCT scanning. These data suggest that pulmonary function tests are useful in assessing and monitoring parenchymal damage in COPD patients.
authors.affiliation: Clinica di Malattie dell'Apparato Respiratorio, Istituto di Ricovero e Cura a Carattere Scientifico Policlinico S. Matteo, Università di Pavia, Pavia, Italy. i.cerveri@libero.it
authors.forename: Isa
authors.initials: I
authors.lastname: Cerveri
authors.forename: Roberto
authors.initials: R
authors.lastname: Dore
authors.forename: Angelo
authors.initials: A
authors.lastname: Corsico
authors.forename: Maria C
authors.initials: MC
authors.lastname: Zoia
authors.forename: Riccardo
authors.initials: R
authors.lastname: Pellegrino
authors.forename: Vito
authors.initials: V
authors.lastname: Brusasco
authors.forename: Ernesto
authors.initials: E
authors.lastname: Pozzi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications* / Q000000981:diagnostic imaging* / Q000503:physiopathology; D011656:Pulmonary Emphysema / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology; D011859:Radiography; D012129:Respiratory Function Tests