Knudson R J, Standen J R, Kaltenborn W T, Knudson D E, Rehm K, Habib M P, Newell J D
Division of Respiratory Sciences, University of Arizona College of Medicine, Tucson 85724.
Chest. 1991 Jun;99(6):1357-66. doi: 10.1378/chest.99.6.1357.
Results of computed tomography of the lung performed at two levels in upper lung zones at full inspiration and full expiration were compared with results of tests of ventilatory function, lung mechanics, and single breath carbon monoxide diffusing capacity in 64 subjects, many of whom had some form of airflow obstruction. From the CT scans, the mean percentage of pixels in the range -900 to -1,024 Hounsfield units, or pixel index, was determined for each subject. The highest correlations of pixel index with physiologic variables consistent with a diagnosis of emphysema were observed for CT taken at full expiration. In some subjects, the inspiratory CT would give a "false positive" for emphysema when the hyperaeration observed at inspiration was not observed at expiration. We believe that the CT scan taken at full expiration can effectively reveal the abnormal permanent enlargement of airspaces which defines emphysema and provides a noninvasive method of assessing lung morphology in the living human subject.
对64名受试者在深吸气和深呼气时上肺区两个层面的肺部计算机断层扫描结果与通气功能、肺力学和单次呼吸一氧化碳弥散能力测试结果进行了比较，其中许多受试者存在某种形式的气流阻塞。通过CT扫描，确定了每个受试者在-900至-1024亨氏单位范围内的像素平均百分比，即像素指数。在深呼气时进行的CT扫描中，观察到像素指数与符合肺气肿诊断的生理变量之间的相关性最高。在一些受试者中，当吸气时观察到的过度充气在呼气时未观察到时，吸气CT会给出肺气肿的“假阳性”结果。我们认为，深呼气时进行的CT扫描可以有效地揭示定义肺气肿的气腔异常永久性扩大，并提供一种在活体人类受试者中评估肺形态的非侵入性方法。
