Assessment of lung volumes using helical CT at inspiration and expiration: Comparison with pulmonary function tests
Assessment of lung volumes using helical CT at inspiration and expiration: Comparison with pulmonary function tests
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DOI：
10.2214/ajr.171.4.9763003
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发表时间：
1998-10-01
影响因子：
5
通讯作者：
Thelen, M
中科院分区：
文献类型：
--
作者：
Kauczor, HU;Heussel, CP;Thelen, M
OBJECTIVE.本研究的目的是确定肺容积使用吸气和呼气螺旋CT二维（2D）和三维（3D）后处理，并比较这些测量的准确性与肺功能测试结果。72例疑似肺部疾病的患者在深吸气和呼气时接受了非增强螺旋CT扫描（层厚8 mm，螺距2，增量8 mm）。使用2D方法（半自动分割;阈值，-1024和-200 H）或3D技术（感兴趣的双阈值种子体积;阈值，-1024 H [下限]和-900、-500、-400、-300或-200 H [上限]）确定肺体积。肺功能检查可用于所有病例的相关性。使用吸气螺旋CT，我们低估了12%的总肺容量，这与静态肺容量有很好的相关性（r = 0.89）。呼气相螺旋CT显示的容积与胸内气体容积相当，两者也具有良好的相关性（r = 0.88）。然而，使用呼气相螺旋CT，我们高估了残气量850 mi，相关性相当好（r = 0.77）。肺气肿指数显示与1秒内的相对用力呼气量中度相关（吸气，r =-0.66，呼气，r =-0.54），而呼气量显示与1秒内的绝对用力呼气量中度相关（r= 0.65）。2D方法显示的绝对体积低于3D技术（平均值，3.6%; r=.99）。在3D技术中，较低的上限阈值导致体积减少（170 ml/100 H）。吸气和呼气螺旋CT显示与静态肺容积高度相关。推荐使用3D技术（-1024至-200 H）进行肺容积的绝对估计。
OBJECTIVE. This study was designed to determine lung volumes using inspiratory and expiratory helical CT with two-dimensional (2D) and three-dimensional (3D) postprocessing and to compare the accuracy of those measurements with pulmonary function test results.SUBJECTS AND METHODS. Seventy-two patients with suspected pulmonary disease underwent unenhanced helical CT (slice thickness, 8 mm; pitch, 2; increment, 8 mm) at deep inspiration and expiration. Lung volumes were determined using either a 2D approach (semiautomatic segmentation; thresholds, -1024 and -200 H) or a 3D technique (double-threshold seeded volumes of interest; thresholds, -1024 H [lower] and -900, -500, -400, -300, or -200 H [upper]). Pulmonary function tests were available for correlation in all cases.RESULTS. Using inspiratory helical CT, we underestimated total lung capacity by 12%, which had a good correlation (r =.89) with static lung volumes. Volume revealed by expiratory helical CT was equivalent to intrathoracic gas volume, which also exhibited a good correlation (r =.88). However, using expiratory helical CT, we overestimated residual volume by 850 mi with a rather good correlation (r =.77). An emphysema index revealed moderate correlation with the relative forced expiratory volume in 1 sec (inspiration, r =-.66, expiration, r =-.54), whereas the expired volume showed a moderate correlation with the absolute forced expiratory volume in 1 sec (r=.65). The 2D approach showed lower absolute volumes than the 3D technique (mean, 3.6%; r=.99). In the 3D technique, lower upper thresholds led to reduced volumes (170 ml/100 H).CONCLUSION. Inspiratory and expiratory helical CT show high correlation with static lung volumes. The 3D technique (-1024 to -200 H) is recommended for absolute estimation of lung volumes.