MSCT测量不同CT阈值下慢性阻塞性肺疾病患者肺潴留体积

MSCT in measurement of pulmonary trapping volume below different CT threshold in patients with chronic obstructive pulmonary disease

目的采用MSCT测量慢性阻塞性肺疾病(COPD)患者不同CT阈值下肺潴留体积。方法对28例COPD患者行64排CT吸气及呼气双相扫描,应用Emphysema软件测量不同CT阈值下(吸气相-950 HU、呼气相-950、-930、-910、-890、-870、-850HU)的肺潴留体积,同时测量吸气末全肺容积(Vin)及呼气末全肺容积(Vex)。比较吸气相-950HU与呼气相不同CT阈值下肺体积占肺总体积的百分比(Vtrap%),分析Vtrap%、Vin和Vex与肺功能参数的相关性。结果不同时相及不同CT阈值下Vtrap%测值不同,呼气相-930HU下与吸气相-950HU下Vtrap%最接近,差异均无统计学意义(P均>0.05)。吸气相-950HU以下和呼气相不同CT阈值下Vtrap%与第1秒用力肺活量与用力肺活量的比值呈负相关;Vin与肺总量、Vex与残气量之间呈正相关。结论 MSCT测量不同CT阈值下肺潴留体积不同,本研究条件下-930HU为呼气相测量COPD患者肺潴留体积的最佳阈值。

Objective To measure the pulmonary trapping volume below different CT threshold with MSCT in patients with chronic obstructive pulmonary disease （COPD）. Methods Twenty-eight COPD patients underwent 64-slice MSCT scanning in both inspiratory and expiratory phase. CT thresholds was set as -950 HU in inspiration phase and -950, -930, -910, -890, -870, -850 HU in expiration phase to measure the trapping volume using Emphysema software. In addition, volume at the end of the inspiratory phases （Vin） and volume at the end of the expiratory phases （Vex） were also measured. Trapping volume percentage （Vtrap%） below different CT thresholds in the expiratory phase and inspiratory phase were compared, and the correlation of Vtrap%, Vin and Vex with lung function were analyzed. Results There were differences of Vtrap% between different phases and different CT thresholds. Vtrap% below -930 HU in the expiratory phase and -950 HU in the inspiratory phase were similar without statistic difference （all P〉0.05）. Vtrap% below -950 HU in the inspiratory phase and below different CT threshold in the expiratory phase negatively correlated with the ratio of forced expiratory volume in one second to forced vital capacity. In addition, there were positive correlation between Vin and total lung capacity as well as Vex and residual volume. Conclusion The value of trapping volume below different CT threshold measured with MSCT is different in patients with COPD, and -930 HU in the expiratory phase is the optimum threshold under the giving conditions.