Functional Hrct Imaging Of The Small Airways Of Long-term Smokers Lung Damage And Pulmonary Function Test-control Study

Objective To evaluate the value of the end-inspiratory and end-expiratory HRCT(functional HRCT) in detecting early stage small airway diseases secondary to cigarette smoking.Materials and Methods The end-inspiratory and end-expiratory HRCT was performed prospectively in 70 subjects(25 nonsmokers and 45 smokers) without any history of pulmonary diseases or present pulmonary symptoms.The smokers were divided into heavy and light grades.Pulmonary function tests(PFTs) were performed in 49 of the 70 subjects immediately after obtaining the HRCT scans.The findings of HRCT and results of PFTs were analyzed.Results The main HRCT findings of the lungs in asymptomatic smokers were centrilobular emphysema in 46.7%,panlobular emphysema in 15.6%,paraseptal emphysema in 42.2%,parenchymal micronodules in 24.4%,pleural micronodules in 31.1%,areas of ground-glass attenuation in 26.7%,dystelectases in dependent lung areas in 8.9%,thickened interlobular septa in 13.3%,pulmonary bullae in 8.9% and air trapping in 47.6%.The main HRCT findings of the lung in nonsmokers were centrilobular emphysema in 12%, paraseptal emphysema in 8%, pleural micronodules in 32%, thickened interlobular septa in 12%, pulmonary bullae in 8% and air tapping in 8%.The incidence of centrilobular emphysema ,paraseptal emphysema ,parenchymal micronodules,areas of ground-glass attenuation and air trapping in smoking group was higher than that in non-smoking group. The incidence of centrilobular emphysema and paraseptal emphysema in heavy smokers was higher than that in light ones.PFTs results were within normal ranges in 46 subjects and abnormal in 3 smokers.Conclusion The functional HRCT is earlier than PFTs in detecting small airway diseases occurred in asymptomatic smokers.The smoker's significant HRCT fingings are centrilobular emphysema ,parenchymal micronodules,areas of ground-glass attenuation and air trapping.