Department of Anesthesiology and Intensive Care Medicine, University Hospital Carl Gustav Carus, Dresden, Germany.
Intensive Care Med. 2010 Nov;36(11):1836-44. doi: 10.1007/s00134-010-2014-2. Epub 2010 Aug 6.
Clinical applications of quantitative computed tomography (qCT) in patients with pulmonary opacifications are hindered by the radiation exposure and by the arduous manual image processing. We hypothesized that extrapolation from only ten thoracic CT sections will provide reliable information on the aeration of the entire lung.
CTs of 72 patients with normal and 85 patients with opacified lungs were studied retrospectively. Volumes and masses of the lung and its differently aerated compartments were obtained from all CT sections. Then only the most cranial and caudal sections and a further eight evenly spaced sections between them were selected. The results from these ten sections were extrapolated to the entire lung. The agreement between both methods was assessed with Bland-Altman plots.
Median (range) total lung volume and mass were 3,738 (1,311-6,768) ml and 957 (545-3,019) g, the corresponding bias (limits of agreement) were 26 (-42 to 95) ml and 8 (-21 to 38) g, respectively. The median volumes (range) of differently aerated compartments (percentage of total lung volume) were 1 (0-54)% for the nonaerated, 5 (1-44)% for the poorly aerated, 85 (28-98)% for the normally aerated, and 4 (0-48)% for the hyperaerated subvolume. The agreement between the extrapolated results and those from all CT sections was excellent. All bias values were below 1% of the total lung volume or mass, the limits of agreement never exceeded ± 2%.
The extrapolation method can reduce radiation exposure and shorten the time required for qCT analysis of lung aeration.
由于辐射暴露和繁琐的手动图像处理，定量计算机断层扫描（qCT）在肺部混浊患者中的临床应用受到限制。我们假设仅从十个胸部 CT 切片推断可以提供有关整个肺部通气的可靠信息。
回顾性研究了 72 例正常肺部和 85 例混浊肺部患者的 CT。从所有 CT 切片中获得了肺及其不同充气部位的体积和质量。然后仅选择最头侧和尾侧的切片以及它们之间的另外八个均匀间隔的切片。将这十个切片的结果推断到整个肺部。使用 Bland-Altman 图评估两种方法之间的一致性。
中位数（范围）全肺体积和质量分别为 3738（1311-6768）ml 和 957（545-3019）g，相应的偏差（一致性界限）分别为 26（-42 至 95）ml 和 8（-21 至 38）g。不同充气部位（全肺体积百分比）的中位数体积（范围）分别为未充气部分 1（0-54）%、充气不足部分 5（1-44）%、正常充气部分 85（28-98）%和过度充气部分 4（0-48）%。推断结果与所有 CT 切片之间的一致性非常好。所有偏差值均低于全肺体积或质量的 1%，一致性界限从未超过±2%。
外推法可以减少辐射暴露并缩短肺部通气 qCT 分析所需的时间。
