King G G, Müller N L, Whittall K P, Xiang Q S, Paré P D
University of British Columbia Pulmonary Research Laboratory, and Department of Radiology, St. Paul's Hospital, Vancouver, BC, Canada.
Am J Respir Crit Care Med. 2000 Feb;161(2 Pt 1):574-80. doi: 10.1164/ajrccm.161.2.9812073.
High-resolution computed tomography (HRCT) has been used to examine airway narrowing. We developed an automated computed tomographic image analysis algorithm (computed tomographic airway morphometry; CTAM) to measure airway lumen area (Ai ), airway wall area (Awa), and airway angle of orientation. Tubes of varying size were embedded in Styrofoam and then scanned at angles between 0 degrees and 50 degrees to assess the accuracy of measurements made with CTAM. Two excised pig lungs were fixed in inflation, sectioned, and scanned. Ai and Awa were measured planimetrically from the cut surfaces to optimize CTAM measurement parameters. In CTAM, Ai was defined according to an airway-size-dependent threshold value, and total Awa was determined through a score-guided erosion method. Results were compared with measurements made through a previously validated method (manual method). CTAM provided accurate measurements of the tubes' Ai values at all angles; Awa was overestimated in direct relation to airway size. The manual method underestimated Ai and overestimated Awa in a manner directly related to airway size as well as to airway angle of orientation. In the excised lung, the mean errors of Ai and Awa measurements made with CTAM were 0.52 +/- 0.24 mm(2) and 0.17 +/- 0.32 mm(2) (mean +/- SEM), respectively. Ai errors with the manual method were similar, but Awa was overestimated to a greater degree (6.3 +/- 0.38 mm(2); p < 0.01) and the error was proportional to Awa (r = 0.64; p < 0.01). CTAM allows accurate measurements of airway dimensions and angle of orientation.
高分辨率计算机断层扫描（HRCT）已被用于检查气道狭窄情况。我们开发了一种自动计算机断层扫描图像分析算法（计算机断层扫描气道形态测量法；CTAM）来测量气道管腔面积（Ai）、气道壁面积（Awa）以及气道方向角度。将不同尺寸的管子嵌入聚苯乙烯泡沫塑料中，然后在0度至50度之间的角度进行扫描，以评估CTAM测量的准确性。对两个切除的猪肺进行充气固定、切片并扫描。从切面以平面测量法测量Ai和Awa，以优化CTAM测量参数。在CTAM中，Ai根据气道大小依赖的阈值进行定义，总Awa通过评分引导的侵蚀方法确定。将结果与通过先前验证的方法（手动方法）进行的测量结果进行比较。CTAM在所有角度都能准确测量管子的Ai值；Awa与气道大小呈直接相关的高估。手动方法也以与气道大小以及气道方向角度直接相关的方式低估了Ai并高估了Awa。在切除的肺中，CTAM测量Ai和Awa的平均误差分别为0.52±0.24mm²和0.17±0.32mm²（平均值±标准误）。手动方法测量Ai的误差相似，但Awa被高估的程度更大（6.3±0.38mm²；p<0.01），且误差与Awa成比例（r=0.64；p<0.01）。CTAM能够准确测量气道尺寸和方向角度。
