Association of findings in flow-volume spirometry with high-resolution computed tomography signs in asbestos-exposed male workers

Disorders of pulmonary tissue and pleura are visualized by findings in high-resolution computed tomography (HRCT), and the impairment caused by these findings is assessed by pulmonary function tests. Our aim was to determine how some commonly used spirometric variables are related to certain HRCT signs, in order to find out which HRCT signs are associated with restrictive and which with obstructive ventilatory impairment.

Altogether 590 asbestos-exposed workers, 95% of whom were smokers or ex-smokers, were studied with HRCT; 19 pathological signs were scored. Forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), FEV1/FVC ratio, forced expiratory flow at 50% of FVC (MEF50) and total lung capacity (TLC) were measured, and their relationship with HRCT signs was examined with bivariate correlations and multiple regression analysis.

FVC and TLC were negatively correlated with fibrosis score, parenchymal bands, extent of pleural thickenings and positively with widened retrosternal space. FEV1/FVC ratio was negatively correlated with emphysema types and widened retrosternal space and positively with parenchymal bands and subpleural nodules. Thickened bronchial walls did not separate between restrictive and obstructive ventilatory function.

HRCT signs showed distinctive patterns in restrictive and obstructive ventilatory impairment. These results can be used to help to analyse the lung function of patients simultaneously exposed to asbestos and smoking, when this relationship requires elucidation. In addition, the results may be helpful in explaining some radiological findings.