Correlation Between CT Parameters In The Inspiration And Expiration And Pulmonary Function Tests In COPD Patients

Objective:Using MSCT to scan the patients with COPD and healthy subjects in the inspiration and expiration.By measuring small airway parameters to analysis of the differences in parameters of small airway between COPD group and healthy subjects group and the relationship between small airway parameters and pulmonary function tests.To study the feasibility and clinical application value of small airway measurement in the diagnosis and evaluation of COPD by MSCT scan in the inspiration and expiration to quantitative measure small airway parameters.Methods:A total of 76 patients with chronic obstructive pulmonary disease(COPD)and 14 healthy volunteers were enrolled.For each patients,CT scan was performed in deep inspiration and expiration.pulmonary function tests(PFT)were performed in less than a week.Pose-processing software was used to measure the small airway of parameters of apical segment of the right upper lobe、apicoposterior segment of the left upper lobe、posterobasal segment of the right lower lobe、posterobasal segment of the left lower lobe,and each airway parameters including wall thickness(WT)、airway luminal area(AI)、airway outer area(AO),and then calculated the preceding ones: airway wall area(WA)and the percentage of airway wall area(WA%).The t test was used to compare the differences of small airway parameters between the COPD group and normal control group.And the Pearson rank test was used to assess the correlation of small airway parameters of COPD group in the inspiration and expiration with PET index.Results:(1)There were significant differences in WT,AI,WA and WA% between the normal control group and the COPD group in inspiratory and expiratory CT(P<0.05).(2)There were significant correlations with WT,AI,WA,WA% of small airway in inspiratory and expiratory CTand PET index in the COPD group.WT,WA,WA% were positively correlated with FEV1 and FEV1/FVC %,and AI negatively correlated with FEV1 and FEV1/FVC%.(3)The correlation coefficients between small airway parameters at expiratory CT and PET index were higher than those for inspiratory CT.(4)At the expiratory CT the correlation coefficients between small airway parameters in the lower lobe and PET index were higher than those in upper lobe.Conclusion:COPD patients with small airway wall thickness than normal healthy people thickening,while the lumen area is gradually reduced.It is feasible that application of MSCT in the inspiration and expiration to quantitative measure small airway parameters to evaluate airflow limitation in COPD patients.And the small airway parameter : wall thickness,airway luminal area,airway wall area and the percentage of airway wall area can be used as indicators to reflect airway changes in COPD patients.MSCT scan in the inspiration and expiration can more fully and dynamically reflect the small airway changes in COPD patients.And the effect of thickening of the lower lobe airway wall on the pulmonary function was greater than that of the upper lobe.