Zinserling Jörg, Wrigge Hermann, Neumann Peter, Muders Thomas, Magnusson Anders, Hedenstierna Göran, Putensen Christian
Department of Anesthesiology and Intensive Care Medicine, University of Bonn, D-53105, Bonn, Germany.
Chest. 2005 Oct;128(4):2963-70. doi: 10.1378/chest.128.4.2963.
In acute lung injury, thoracic CT is used to gain information about lung aeration and consolidation. This can be done either during breath-holding by spiral CT scanning of the entire lung or dynamically by scanning lung slices without interrupting ventilation. We hypothesized that attenuation distribution is dependent on static or dynamic scanning techniques. We also studied whether a variation in the CT cut level, corresponding to the diaphragm movement over a breath, had any effect on the attenuation distribution.
Twenty-two pigs with oleic acid-induced lung injury were randomly assigned to receive pressure-controlled mechanical ventilation with or without spontaneous breathing. Transversal dynamic CT scans of the chest were performed in apical and juxtadiaphragmatic regions, and end-expiratory and end-inspiratory slices were selected. In addition, after clamping the tube at end-expiration and end-inspiration, respectively, spiral CTs were performed. Guided by morphologic structures, spiral CT slices matching the dynamic scan slice and three additional neighbored slices above the diaphragm were selected. Distributions of CT attenuation were calculated and summarized in ranges for comparison.
No significant difference in attenuation distributions between the two scanning methods or an interaction with the factors ventilation mode, ventilation phase, and attenuation range were found. In addition, attenuation distributions of four neighbored juxtadiaphragmatic slices, 8 mm thick, from the spiral CT did not differ statistically.
In an animal model of oleic acid-induced lung injury, analyses of transverse thoracic slices based on dynamic or static CT scanning showed comparable distributions of attenuation. Variations on the CT cut level of 24 mm had no significant effect on the distribution of Hounsfield unit numbers. CT attenuation distributions of transversal juxtadiaphragmatic slices were not dependent on exact position.
在急性肺损伤中，胸部CT用于获取有关肺通气和实变的信息。这可以通过屏气时对整个肺部进行螺旋CT扫描来完成，也可以在不中断通气的情况下对肺切片进行动态扫描来实现。我们假设衰减分布取决于静态或动态扫描技术。我们还研究了与呼吸过程中膈肌运动相对应的CT扫描层面的变化是否对衰减分布有任何影响。
将22只油酸诱导的肺损伤猪随机分配接受有或无自主呼吸的压力控制机械通气。在肺尖和膈旁区域进行胸部横向动态CT扫描，并选择呼气末和吸气末切片。此外，分别在呼气末和吸气末夹闭气管后，进行螺旋CT扫描。在形态学结构的引导下，选择与动态扫描切片匹配的螺旋CT切片以及膈肌上方另外三个相邻切片。计算CT衰减分布并汇总成范围进行比较。
两种扫描方法之间的衰减分布没有显著差异，也未发现与通气模式、通气阶段和衰减范围等因素存在相互作用。此外，螺旋CT扫描的四个相邻膈旁8毫米厚切片的衰减分布在统计学上没有差异。
在油酸诱导的肺损伤动物模型中，基于动态或静态CT扫描对胸部横向切片进行分析显示衰减分布具有可比性。24毫米的CT扫描层面变化对亨氏单位数的分布没有显著影响。横向膈旁切片的CT衰减分布不依赖于确切位置。
