The Study Of Early Pulmonary Functional And Small Airway’s Changes In Asbestosis Patients Using Multi-slice CT

Objective: We used multi-slice spiral CT in asbestosis patients and normal volunteers by inspiratory and expiratory scan, to observe the characteristic changes of pulmonary function and small airway in asbestosis patients, to evaluate the relation between the changes of pulmonary function, small airway with stage, contact history and the type-of work. Methods: Each subject had a whole lung scanning both in inspiratory and expiratory breath, the Siemens Pulmo quantitative analysis software was used to determine below pulmonary volume indices: ① inspiratory and expiratory lungs volume(Vin, Vex), left lung volume(VinL, VexL), right lung volume(VinR, VexR), volume difference(Vin-Vex), volume ratio(Vex/Vin), ② the mean lung density indices: inspiratory and expiratory mean lungs density(MLDin, MLDex), left lung mean density(MLDinL, MLDexL), right lung mean density(MLDinR, MLDexR), density difference(MLDex-MLDin), density ratio(MLDex/MLDin), ③ the apical segmental bronchus of the right upper lobe: inner diameter(1umen diameter), outer diameter(airway diameter), diameter ratio(TDRin% TDRex%) and wall area percentage(WAin% WAex%). SPSS 17 statistical software was used to do independent samples t test between asbestosis patients groups with normal control group, covariance analysis between normal control group with asbestosis patients groups in stage, in contact history and in different types-of work(age is covariant), contingency-table analysis between contact history groups and the types of work groups with stage. Results: ① Asbestosis patients abnormal pulmonary function indices are: Vin, VinL, VinR, VexR, Vin-Vex, Vex/Vin, MLDex, MLDexL, MLDexR, MLDex-MLDin and MLDex/MLDin, abnormal small airway indices are: TDRin, WA%in, TDRex and WA%ex. ② Asbestosis patients II group right lung residual volume significantly increasing with stage, asbestosis patients I and II groups forced vital capacity decrease, but not significantly decreased with stage, asbestosis patients I and II groups inspiratory and expiratory phase small airway wall thicken, but not significantly thickening with stage. ③ 16 years is the critical value, asbestos workers expose to asbestos in 16 years two lungs, left lung, right lung residual volume increases, emphysema, forced vital capacity decreased but not aggravated with contact history. Asbestosis patients appear inspiratory phase of small airway wall thicken but not significantly thicken with contact history. ④ The pulmonary function decreased significantly in combing group no significant difference of small airway wall thicken was found between the groups. ⑤ Contact history had significant correlation with stage but not found with the type-of work. Conclusion: We can found the early changes of pulmonary function and small airway in asbestosis more earlier with CT: ① In asbestosis patients, left, right and total lungs capacity decreased, left, right and total lungs residual volume increased, forced vital capacity decreases, emphysema, inspiratory and expiratory phase of small airway wall were thicken.② Asbestosis patients right lung residual volume significantly increasing with stage, forced vital capacity decreased but not significantly reduced with stage, the inspiratory and expiratory phase of small airway wall was thicken but no significant with stage. ③ Asbestosis patients firstly appeared small airway changes, followed by the changes of pulmonary function(16 years of the asbestos exposure is risk history in our group). ④ Pulmonary function damaged heavier in combing group, three groups had no significant difference in small airway changes. ⑤ Contact history has significant correlation with stage but not found with the type-of work.