Department of Radiology, Peking University Third Hospital, Beijing 100191, People's Republic of China.
Med Phys. 2013 Aug;40(8):082103. doi: 10.1118/1.4813906.
The purpose of this study was to evaluate the effect of various computed tomography (CT) thresholds on trapping volumetric measurements by multidetector CT in chronic obstructive pulmonary disease (COPD).
Twenty-three COPD patients were scanned with a 64-slice CT scanner in both the inspiratory and expiratory phase. CT thresholds of -950 Hu in inspiration and -950 to -890 Hu in expiration were used, after which trapping volumetric measurements were made using computer software. Trapping volume percentage (Vtrap%) under the different CT thresholds in the expiratory phase and below -950 Hu in the inspiratory phase was compared and correlated with lung function.
Mean Vtrap% was similar under -930 Hu in the expiratory phase and below -950 Hu in the inspiratory phase, being 13.18±9.66 and 13.95±6.72 (both lungs), respectively; this difference was not significant (P=0.240). Vtrap% under -950 Hu in the inspiratory phase and below the -950 to -890 Hu threshold in the expiratory phase was moderately negatively correlated with the ratio of forced expiratory volume in one second to forced vital capacity and the measured value of forced expiratory volume in one second as a percentage of the predicted value.
Trapping volumetric measurement with multidetector CT is a promising method for the quantification of COPD. It is important to know the effect of various CT thresholds on trapping volumetric measurements.
本研究旨在评估在慢性阻塞性肺疾病（COPD）中，使用多层螺旋 CT（MDCT）对不同 CT 阈值下的容积测量结果的影响。
23 例 COPD 患者在吸气和呼气阶段进行 64 层 CT 扫描。在吸气时使用-950 Hu 的 CT 阈值，在呼气时使用-950 至-890 Hu 的 CT 阈值，然后使用计算机软件进行容积测量。比较呼气阶段下不同 CT 阈值和吸气阶段低于-950 Hu 下的容积百分比（Vtrap%），并与肺功能相关联。
呼气阶段下-930 Hu 与吸气阶段低于-950 Hu 时的平均 Vtrap%相似，分别为 13.18±9.66 和 13.95±6.72（双肺）；差异无统计学意义（P=0.240）。吸气阶段低于-950 Hu 与呼气阶段低于-950 至-890 Hu 阈值时的 Vtrap%呈中度负相关，与一秒用力呼气容积与用力肺活量的比值以及一秒用力呼气容积实测值占预计值的百分比呈中度负相关。
使用多排螺旋 CT 进行容积测量是一种定量评估 COPD 的有前途的方法。了解不同 CT 阈值对容积测量的影响非常重要。
