呼吸双相定量CT对慢性阻塞性肺疾病临床症状与肺功能评价

Paired inspiratory and expiratory quantitative CT in evaluation of clinical symptoms and pulmonary function in chronic obstructive pulmonary disease

目的:探讨呼吸双相CT定量参数对慢性阻塞性肺疾病(COPD)临床症状与肺功能的影响。方法:205例患者行呼吸双相肺部CT,测量肺密度参数包括肺气肿指数(EI)、空气潴留(AT)、平均肺密度(MLD),容积参数为全肺容积(TLC)。患者于检查当日填写COPD评估测试(CAT),并行肺功能检查,包括FEV1/FVC、FEV1%及RV/TLC。分析CT定量参数与CAT评分、肺功能指标相关性并进行多元线性回归分析。结果:CT肺密度参数与CAT评分(r=0.220~0.293,P=0.000~0.005)和各项肺功能指标(r=0.320~0.730,P<0.001)均有显著相关性。EI与CAT评分的相关系数大于其它CT参数,是CAT评分独立影响因素(P<0.001);呼气相MLD、TLC和AT与肺功能相关系数分别高于吸气相MLD、TLC和EI。回归分析AT对各项肺功能指标贡献(P<0.001)均>EI。结论:吸气相EI是症状评分独立影响因素,呼气相CT定量参数较吸气相对肺功能影响更大,呼吸双相定量CT可更好地反映COPD临床与肺功能状况。

Objective:To investigate the effectiveness of paired inspiratory and expiratory quantitative CT parameters in evaluation of clinical symptoms and pulmonary function in patients with chronic obstructive pulmonary diseases(COPD).Methods:The study population were randomly selected from outpatients in our hospital via questionnaires.205 participants underwent biphasic low-dose volumetric chest CT scan at full-inspiration and full-expiration phase.Emphysema index(EI),air trapping(AT),mean lung density(MLD)and total lung capacity(TLC)were measured on CT densitometry.The COPD assessment tests(CAT)were completed on the same day.Pulmonary functional test(PFT)parameters were also obtained,including forced expiratory volume in one second percent predicted(FEV1%),forced expiratory volume in one second to forced vital capacity ratio(FEV1/FVC)and residual volume to total lung capacity ratio(RV/TLC).The correlations between CT measurements and symptom scores,as well as the PFT parameters were evaluated.Multiple linear regression was used to analyze the correlations between them.Results:CT density,including EI,AT and MLD,significantly correlated with symptom scores(r=0.220~0.293,P=0.000~0.005),as well as the PFT parameters(r=0.320~0.730,P<0.001).EI exhibited the strongest correlation with CAT score,while expiratory quantitative CT parameters exhibited stronger correlations than paired inspiratory CT parameters with the PFT parameters.EI is an independent influencing factor of CAT scores,FEV1%,and FEV1/FVC respectively.AT is independent influencing factors to FEV1%,FEV1/FVC and RV/TLC,and the contribution of AT is greater than EI for every PFT parameter.Conclusion:Inspiratory CT parameters of EI are independent influencing factors of symptom scores,whereas expiratory CT parameters have greater impacts on PFT parameters.Paired inspiratory and expiratory quantitative CT may well reflect clinical and functional status in patients with COPD.