Asbestos-induced and smoking-related disease: apportioning pulmonary function deficit by using thin-section CT.
OBJECTIVE
To retrospectively correlate the extent of individual diseases seen at thin-section computed tomography (CT) with pulmonary function in an initial group of patients with asbestos-related parenchymal disease (asbestosis) and to test these findings in a subsequent group of patients whose CT scans were retrospectively identified.


METHODS
This retrospective study had Institutional Review Board approval; informed consent was not required. The study included 133 individuals who had been exposed to asbestos. In the initial study group (81 patients; 79 men, two women; median age, 67 years), two observers used a CT scoring system to quantify the extent of pulmonary fibrosis, diffuse pleural thickening, small-airways disease, and emphysema. Multivariate equations were formulated by using independent CT variables to predict changes in total lung capacity (TLC) and carbon monoxide diffusing capacity (Dlco). The validity of these equations was then tested in a subsequent group of patients (52 patients; all men; median age, 60 years).


RESULTS
At thin-section CT, the extent of asbestos-induced pleuropulmonary disease and emphysema correlated significantly with physiologic impairment (P<.001). Combined CT variables predicted 58% and 57% of the variability in TLC and Dlco, respectively, despite considerable variation in the proportion of coexisting pathologic conditions. When predictive equations with CT variables derived from the initial study group were applied to the subsequent study group, predicted TLC (rho=0.75, P<.001) and Dlco (rho=0.64, P<.001) correlated strongly with measured values.


CONCLUSIONS
The proposed CT system provides a semiquantitative method for assessing the relative contribution of asbestos-induced pleuropulmonary disease and smoking-related emphysema to functional impairment.
Copley
Susan J
SJ
Department of Radiology, Hammersmith Hospital, and Center for Respiratory Research, University College London, London, England.
Lee
Y C Gary
YC
Hansell
David M
DM
Sivakumaran
Pathmanathan
P
Rubens
Michael B
MB
Newman Taylor
Anthony J
AJ
Rudd
Robin M
RM
Musk
A William
AW
Wells
Athol U
AU
D000368:Aged; D019412:Anatomy, Cross-Sectional / Q000379:methods; D001195:Asbestosis / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D011656:Pulmonary Emphysema / Q000000981:diagnostic imaging* / Q000209:etiology*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012129:Respiratory Function Tests / Q000379:methods*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012907:Smoking / Q000009:adverse effects*; D014057:Tomography, X-Ray Computed / Q000379:methods*