64层螺旋CT低剂量双相扫描肺密度在COPD患者肺功能评价中的应用研究

摘要

目的:探讨64层螺旋CT(spiral CT,SCT)低剂量双相扫描肺密度测定在慢性阻塞性肺部疾病(chronic obstructive pulmonary disease,COPD)患者肺功能评价中的应用价值.方法:选择经临床肺功能检查确诊的COPD患者36例(COPD组)和30例无任何心肺疾患且胸部CT检查正常的健康体检者(正常对照组).两组研究对象均采用德国Siemens SOMATOM Sensation 64层SCT机进行深吸气末、深呼气末的全肺低剂量(50 mAs)扫描.按扫描层数将全肺分为上、中、下3个肺区.利用Pulmo软件,分别测量和计算出COPD组与正常对照组深吸气末、深呼气末上、中、下肺区及全肺的各密度指标:深吸气末密度(Din)、深呼气末密度(Dex)、密度差(Dex-Din)、密度比(Dex/Din)、密度变化百分比(Din-Dex)/Din.所有COPD患者均在SCT检查前后3d内完成肺功能检测(pulmonary function tests,PFT),指标为第1秒用力肺活量的实测值与预计值的比值(FEV1％)及第1秒用力肺活量与用力肺活量的比值(FEV1/FVC).比较COPD组与正常对照组之间SCT各密度指标,利用Pearson相关分析来检验各密度指标与肺功能指标FEV1％和FEV1/FVC的相关性.结果:COPD组与正常对照组比较,Din在上、中、下及全肺区的差异有统计学意义(P＜0.05)；Dex,Dex-Din,Dex/Din,(Din-Dex)/Din在各肺区及全肺区的差异亦有统计学意义(P＜0.01).Dex,Dex-Din,Dex/Din,(Din-Dex)/Din均分别与FEV1％,FEV1/FVC有良好的相关性(P＜0.01).结论:64层SCT低剂量双相扫描能便捷、准确地获得评价COPD肺功能的密度指标,与FEV1％和FEV1/FVC两项肺功能指标相关性良好,可用于评估COPD患者的肺功能状况,有较高的临床应用价值.%Objective: To explore the value of 64 slice spiral CT (SCT) low-dose chest scanning at full inspiration and full expiration for lung density measurement in assessing the pulmonary function in patients with chronic obstructive pulmonary disease (COPD). Methods: Totally 36 COPD patients (the COPD group) underwent pulmonary function tests (PFT) and were essentially verified COPD; 30 healthy people (the control group) were selected whose 64 slice SCT chest scanning was normal. The 2 groups underwent chest 64 slice SCT low-dose scanning at full inspiration and full expiration. After the scanning, the lung was measured by CT Pulmo software. The lung was divided into 3 regions by scanning layers. We measured and calculated the density indexes of each region (including the upper, middle, lower field, and the total lung) of the 2 groups. All density indexes were lung density at full inspiration and full expiration (Din, Dex), density difference (Dex-Din), density ratio (Dex/ Din), density variation percentage (Din-Dex)/Din. All patients underwent PFT and 64 slice SCT within 3 days, whose pulmonary function was tested by Master Lab (Jaeger, Germany). The indexes were the percentage of actual value and expected value of forced expiratory volume at the first second (FEV1％) and the ratio of first second forced expiratory volume to forced vital capacity (FEV1/FVC). Then we compared with the CT indexes between the COPD group and the control group. The relevant indicators of lung densities were analyzed in comparison with the indicators of FEV1% and FEV1/FVC by Pearson correlation analysis.Results: The density indexes of each region and total lung, and the Din in the control group and the COPD group were compared. The difference between them was statistically significant (P<0.05). The difference among other indexes was also statistically significant (P<0.01). Excellent correlation was found between Dex, Dex-Din, Dex/ Din and (Din-Dex)/ Din indexes with FEV1% and FEV1/FVC (r=0.566, 0.686, 0.568, 0.580, -0.565, -0.598, 0.565 and 0.598; P<0.01)Conclusion: Sixty-four slice SCT low-dose two-phase scanning density indexes are closely related to the indicators (FEV1％ and FEV1/FVC) of clinical lung function tests, which can be used to evaluate the lung function in COPD patients conventiently and accurately.