Correlation Study On Airflow Limitation In Patients With Chronic Obstructive Pulmonary Disease Using Quantitative Computed Tomography

Objective:To evaluate the relative contributions of emphysema and airway wall thickness measured by quantitative computed tomography(CT)to the prediction of airflow limitation.Materials and Methods:Eighty consecutive cases(40 COPD cases and 40 normal people)were performed pulmonary function tests and Spiral CT exams in Qianfoshan Hospital Affiliated to Shandong University.The data of images were processed in work station of adw4.5rt to get the square root of wall area of a hypothetical airway with an internal area of 8 mm~2(Ai8)and the percentage of low attenuation volume(LAV%)at the threshold of-950 Hounsfield units.The Ai8 between the observation group and the control group was compared by statistical analysis.The relative contributions of LAV%and Ai8 to predictions of FEV1/FVC and FEV1%predicted were also evaluated by statistical analysis.Results:There is obviously statistical difference in the Ai8 between the observation group and the control group.Both LAV%and Ai8 independently predicted FEV1%predicted and FEV1/FVC(P<0.05 for all standardized coefficients).Only the Ai8 of right inferior lobar make a Significantly contribution to airflow limitation in the whole lung,and the LAV%of every lobes make a stronger contribution to airflow limitation than the Ai8 of right inferior lobar.Conclusions:There is obviously statistical difference in the Ai8 between the observation group and the control group.The LAV%may make a greater contribution to airflow limitation than Ai8 in COPD.The order of influence factor of airflow limitation should be:LAV%>Ai8 of right inferior lobar>Ai8 of other lobers.