Pulmonary emphysema: Quantitative CT during expiration
Pulmonary emphysema: Quantitative CT during expiration
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DOI：
10.1148/radiology.199.3.8638012
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发表时间：
1996-06-01
期刊：
影响因子：
19.7
通讯作者：
Yernault, JC
中科院分区：
文献类型：
--
作者：
Gevenois, PA;DeVuyst, P;Yernault, JC
目的：确定呼气时CT薄层扫描衰减系数小于某一阈值的肺相对面积测量是否为一种有价值的量化肺气肿程度的方法。材料和方法：89例患者在术前吸气和呼气时进行CT扫描(准直1 mm)。计算衰减系数小于各阈值的肺相对面积。将这些相对面积与肉眼发现肺气肿的59例患者(男51例，女8例；年龄40~77岁)和两项显微指标(35例患者[男29例，女6例；年龄42~77岁])进行比较。结果：显微肺气肿和肉眼肺气肿的有效呼气CT阈值分别为-820和-910HU。然而，逐步多元回归分析结果显示，吸气阈值-950HU对于宏观和微观量化的肺气肿都是更好的。结论：呼气相CT对肺气肿的定量诊断不如吸气相CT准确，可能更多地反映肺泡壁的空气滞留，而不是肺泡壁的减少。
PURPOSE: To determine whether measurement of the relative area of lung with attenuation coefficients lower than a certain threshold on thin-section computed tomographic (CT) scans obtained during expiration is a valuable method of quantifying the extent of pulmonary emphysema.MATERIALS AND METHODS: Eighty-nine patients underwent CT (with 1-mm collimation) preoperatively during inspiration and expiration. Relative areas of lung with attenuation coefficients lower than various thresholds were calculated. These relative areas were compared with areas found macroscopically to have emphysema (59 patients [51 men, eight women; aged 40-77 years]) and with two microscopic indices (35 patients [29 men, six women; aged 42-77 years]) assessed on the resected specimens.RESULTS: The valid expiratory CT thresholds were found to be -820 and -910 HU for microscopic and macroscopic emphysema, respectively. However, results of stepwise multiple regression analyses showed that the inspiratory threshold of -950 HU was superior for both macroscopically and microscopically quantified emphysema. The correlation coefficients in expiratory CT were higher for the pulmonary volumes but similar for the diffusing capacity.CONCLUSION: Expiratory quantitative CT is not as accurate as inspiratory CT for quantifying pulmonary emphysema and probably reflects air trapping more than reduction in the alveolar wall surface.