Lung Function Correlate With Quantitative CT Parameters In Patients With Chronic Obstructive Pulmonary Disease At High Altitude

Objective: To evaluate the correlation between quantitative computed tomography(CT)parameters and pulmonary function test in patients with chronic obstruction pulmonary disease(COPD)at high altitude.Methods: This study included 83 patients with COPD who underwent HRCT and did the pulmonary function test in 7 days from December 2018 to December 2019.24 patient who did not meet the inclusion criteria or whose diagnosis was other pulmonary diseases were excluded.Finally,16 cases were stage 0,11 cases were stage 1,11 cases were stage 2,11 cases were stage 3 and 10 cases were stage 4 in our study.The included patients were scanned by GE Revolution 256-slice CT at full inspiration and expiration and the reconstructed data were transferred into Thoracic VCAR software for post-processing.The post-processing workstation of parenchyma analysis worked out the parameters as follows: %LAA,WA,WT,LID,LWD,LA,TD,WA%.To evaluate the correlation between pulmonary function test and quantitative CT parameters in patients with chronic obstructive pulmonary disease at high altitude.Results: 1.There was a significant difference in LAA% in each lobe of COPD Patients at all levels during inspiration phase and expiration Phase(all P < 0.05),among which LAA% in each lobe of the right lung of COPD patients at stage 3 and stage 4 were significantly higher than that at stage 0(all P < 0.05).There was no significant difference in residual quantitative CT parameters WA,WT,LID,LWD,LA,TD% and WA% among COPD groups(all P >0.05).2.In 59 cases of COPD FEV1/FVC,FEV1%Pred,MEF25,MEF75,MEF75/25 and DLCO/VA were significantly correlated with the pulmonary LAA% in the inspiratory phase(all P < 0.05).The correlation between pulmonary function tests and expiratory phase quantitative CT LAA% in patients with COPD is unstable,which is affected by the measured location and bronchial level.The significant correlations between airway parameters and lung function tests were found for the 3rd bronchus of the lower right lobe during expiration with P-values between 0.006 and 0.048.The correlation strength for these pairs ranged from-0.260 to-0.345.The most significant correlations were found for the 4rd generation bronchus in the upper left lobe during inspiration with P-values between 0.002 and 0.035.The correlation strength for these pairs varied between-0.275 and-0.394.3.The significant correlations between airway parameters and pulmonary function tests were found for the 3rd bronchus of the lower right lobe during inspiration phase and expiration phase with P-values between 0.001 and 0.030.The correlation strength for these pairs ranged from--0.543 to-0.766.Conclusions: 1.CT measurements of the %LAA,LID,LWD,TD%,WA% are significantly related to pulmonary function test in patients with COPD at high altitude.Quantitative CT parameters were used as a complementary diagnostic tool for PFTs in COPD at high altitude;2.Correlations between pulmonary function test and quantitative CT parameters vary widely between breathing states,lobes and bronchus generations in Pre-COPD patients at high altitude.2.Quantitative CT parameters of Pre-COPD patients at high altitude can provide certain information for airway obstruction,which need further research mainly because there are many influencing factors.