动态CT扫描在慢性阻塞性肺病中的应用研究

Evaluation of Chronic Obstructive Pulmonary Disease with Dynamic Expiratory CT Scans

目的 :探讨和定量分析慢性阻塞性肺疾病 (COPD)患者动态CT扫描的表现及其应用价值。材料和方法 :34例COPD患者分别进行呼、吸气末动态CT扫描及肺功能检查。以呼、吸气末肺野密度变化、像素指数 (PI)值作为CT评价指标。观察上述指标在左、右侧肺 ,上、中、下肺区及前、后肺区的变化规律 ,并比较全肺和局部感兴趣区 (ROI)法对肺野密度测量结果的相关性及以上CT分析参数值与肺功能参数值的相关性。结果 :COPD患者呼、吸气末CT值和CT值差值呈节段性差异。上肺区低于下肺区 ,前肺区低于后肺区 ,此差异在呼气末更显著 (P<0.05) ;左右肺之间各参数值无差异 (P>0.1)。呼气末PI值低于吸气末。全肺法测量结果与局部ROI法显著相关 (P<0.05)。呼、吸气末CT值差值及PI值与反映气流阻塞 (FEV1、FEV1/FVC)及气体潴留 (RV、RV/TLC)的肺功能参数均相关 ,且呼气末相关性大于吸气末 (P<0.05)。结论 :COPD患者存在气体潴留 ,呼气末CT参数值与反映气流阻塞及气体潴留的相应肺功能参数有良好相关性 。

Purpose:To assess and quantify the dynamic CT findings in patients with chronic obstructive pulmonary disease(COPD).Materials and Methods:Thirty-four patients with COPD underwent full respiratory CT scans and pulmonary function tests(PFTs)respectively.The lung attenuation and pixel index(PI)were calculated.CT attenuation was calculated by the ROI method and the whole lung method.These two methods were compared.The three parameter were studied among different lung levels and correlated with the results of PFTs.Results:In COPD patients the CT value and gradient were lower in the upper and indepenent lobe,while higher in the lower and dependent lobe.There differences were more sigˉnificant in expiration phase(P<0.05).There was no significant difference between the right and left lung(P>0.1).The CT value of the lung calculated by the ROI method and the whole lung method showed high correlation(P<0.05).The parameters in quantitative CT were correlated well with the parameters reˉflected air flow obstruction in PFTs and the coefficient of correlation at expiration was higher than inˉspiration(P<0.05).Conclusions:The COPD patients have obviously air trapping,which can be diagˉnosed and quantified by dynamic CT scans,which were correlated well with the parameters in PFTs and seems to be a promising method.