1 National Institute of Health Research Biomedical Research Unit in Respiratory Disease , University Hospital Southampton NHS Foundation Trust, Southampton, UK .
J Aerosol Med Pulm Drug Deliv. 2014 Feb;27(1):35-42. doi: 10.1089/jamp.2012.1029. Epub 2013 Mar 5.
Determination of the lung outline and regional lung air volume is of value in analysis of three-dimensional (3D) distribution of aerosol deposition from radionuclide imaging. This study describes a technique for using computed tomography (CT) scans for this purpose.
Low-resolution CT scans of the thorax were obtained during tidal breathing in 11 healthy control male subjects on two occasions. The 3D outline of the lung was determined by image processing using minimal user interaction. A 3D map of air volume was derived and total lung air volume calculated. The regional distribution of air volume from center to periphery of the lung was analyzed using a radial transform and the outer-to-inner ratio of air volume determined.
The average total air volume in the lung was 1,900±126 mL (1 SEM), which is in general agreement with the expected value for adult male subjects in the supine position. The fractional air volume concentration increased from the center toward the periphery of the lung. Outer-to-inner (O/I) ratios were higher for the left lung [11.5±1.8 (1 SD)] than for the right [10.1±0.8 (1 SD)] (p<0.001). When normalized for the region sizes, these ratios were 1.37±0.16 and 1.20±0.04, respectively. The coefficient of variation of repeated measurement of the normalized O/I ratio was 5.9%.
A technique for outlining the lungs from CT images and obtaining an image of the distribution of air volume is described. The normal range of various parameters describing the regional distribution of air volume is presented, together with a measure of intrasubject repeatability. This technique and data will be of value in analyzing 3D radionuclide images of aerosol deposition.
在放射性核素成像分析中，确定肺轮廓和区域性肺气量对于分析气溶胶沉积的三维（3D）分布具有重要价值。本研究描述了一种使用计算机断层扫描（CT）扫描实现此目的的技术。
在两次呼吸期间，11 名健康男性对照者在仰卧位进行了胸部低分辨率 CT 扫描。使用图像处理方法，通过最小的用户交互确定了肺的 3D 轮廓。得出了空气量的 3D 图谱，并计算了总肺气量。使用径向变换分析了从肺中心到外周的空气量分布，并确定了空气量的外到内比。
肺的平均总气量为 1900±126 毫升（1 个标准差），与仰卧位成年男性的预期值基本一致。空气量的分数浓度从肺的中心向周边增加。左肺的外到内（O/I）比值[11.5±1.8（1 个标准差）]高于右肺[10.1±0.8（1 个标准差）]（p<0.001）。当按区域大小进行归一化时，这些比值分别为 1.37±0.16 和 1.20±0.04。重复测量归一化 O/I 比值的变异系数为 5.9%。
描述了一种从 CT 图像中勾勒出肺并获取空气量分布图像的技术。提出了描述空气量区域性分布的各种参数的正常范围，以及测量个体内重复性的方法。该技术和数据将有助于分析 3D 放射性核素气溶胶沉积图像。
