吸烟者小气道的MDCT呼吸双相定量分析及与肺功能的相关性研究

Analysis of Small Airway Dimensions at Inspiratory and Expiratory Phase MDCT Scan in Smokers and Correlation with Pulmonary Function Test

目的定量分析吸烟人群在多排螺旋CT(MDCT)呼吸双相扫描下的气道径线,并探索其与肺功能的相关性。方法回顾性分析纳入58例吸烟者,经肺功能检查证实其中14例为COPD患者,另纳入39名不吸烟且肺功能正常的人群作为对照组,97名受试者均接受肺功能检查和MDCT呼吸双相扫描。测量所有受试者3~6级气道吸气末的管壁厚度(I-T)、管腔面积(I-LA),管壁面积占横截面积的百分比(I-%WA)及腔面积的呼吸气末比值(E/I-LA),及各参数与肺功能指标中第1秒用力呼气量(FEV_1)、FEV_1实测值与预计值的比值(FEV_1%)、FEV_1与用力肺活量的比值(FEV_1/FVC)、及一氧化碳/肺泡扩散量(DLCO/VA%)的相关性。结果三组人群气道径线中I-LA3~5,I-T6,I-%WA5,E/I-LA3~6以及肺功能参数中FEV_1、FEV_1/FVC、DLCO/VA%均存在明显统计学差异(P<0.05)。吸烟COPD组I-T与DLCO/VA%、E/I-LA与FEV_1/FVC,I-%WA6与FEV_1/FVC均呈明显负相关性,且I-T与DLCO/VA%相关性随3~6级气道减小而增大;I-LA4与FEV_1/FVC呈正相关。吸烟非COPD组的FEV_1与I-LA4、I-%WA4及E/I-LA3,FEV_1%与I-%WA6、DLCO/VA%与I-LA6均呈明显负相关性,且FEV_1与E/I-LA4的相关性较E/I-LA3,I-LA4增大。不吸烟对照组的I-T与DLCO/VA%,I-%WA4与FEV_1,E/I-L4与FEV_1呈明显负相关性。结论 MDCT双气相扫描能有效评价吸烟者小气道改变,且较肺功能检查能更早的发现吸烟者小气道的异常。

Objective To analyse the airway dimensions in smokers,under multi-detector computed tomography（ MDCT） scan at inspiratory and expiratory phase,and to explore its correlation with pulmonary function test. Methods We enrolled 58 smokers,and 14 were found to be COPD patients by pulmonary function test（ PFT）,another 39 non-smokers without COPD were chosen as a control group. All the 97 subjects underwent inspiratory and expiratory phase MDCT scan after PFT. Measure the airway dimensions,including inspiratory wall thickness（ I-T）,luminal area（ I-LA）,wall area percentage（ I-% WA） and the ratio of LA at inspiratory and expiratory phase MDCT（ E/I-LA）,and explore the correlation with PFT indexes,including forced expiratory volume at 1 second（ FEV_1）,forced expiratory volume at 1 second%（ FEV_1%,%）,the ratio of FEV_1 and forced vital capacity（ FEV_1/FVC,%）,and the ratio of the diffusion capacity of the lung for carbon monoxide and alveolar volume（ DLCO/VA%）. Results Among the three groups,Significant difference was found in airway dimensions including I-LA3 ~ 5,I-T6,I-% WA5 and E/I-LA3 ~ 6（ P〈0. 05）,and PFT parameters such as FEV_1、FEV_1/FVC and DLCO/VA%（ P〈0. 05）. There was negative correlation between I-T and DLCO/VA%,E/I-LA as well as FEV_1/FVC,I-% WA6 与 FEV_1/FVC in COPD patients,and the correlation coefficient between I-T and DLCO/VA% increased with the airways getting smaller from 3rd to 6th. I-LA4 and FEV_1/FVC was positively correlated in COPD patients. In smokers without COPD,FEV_1 and I-LA4,I-% WA4 as well as E/I-LA3,FEV_1% and I-% WA6、DLCO/VA% and I-LA6 showed negative correlation. The correlation coefficient of FEV_1 with E/I-LA4 was greater than with E/I-LA3 and I-LA4. In non-smoker controls,there was negative correlation between I-T and DLCO/VA%,I-% WA4 and FEV_1,E/I-L4 and FEV_1. Conclusion Compared with PFT,MDCT scan in the inspiratory and expiratory phase can evaluate small airways changes of smokers effectively,and detect the abnormal airways earlier.