Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins Medical Institutions, Baltimore, Maryland;
Department of Radiology, The Johns Hopkins Medical Institutions, Baltimore, Maryland.
J Appl Physiol (1985). 2017 Oct 1;123(4):876-883. doi: 10.1152/japplphysiol.00307.2017. Epub 2017 Jul 13.
Reproducibility of airway luminal size in asthma measured by HRCT. 123: 876-883, 2017. First published July 13, 2017; doi:10.1152/japplphysiol.00307.2017.-High-resolution CT (HRCT) is a well-established imaging technology used to measure lung and airway morphology in vivo. However, there is a surprising lack of studies examining HRCT reproducibility. The CPAP Trial was a multicenter, randomized, three-parallel-arm, sham-controlled 12-wk clinical trial to assess the use of a nocturnal continuous positive airway pressure (CPAP) device on airway reactivity to methacholine. The lack of a treatment effect of CPAP on clinical or HRCT measures provided an opportunity for the current analysis. We assessed the reproducibility of HRCT imaging over 12 wk. Intraclass correlation coefficients (ICCs) were calculated for individual airway segments, individual lung lobes, both lungs, and air trapping. The ICC [95% confidence interval (CI)] for airway luminal size at total lung capacity ranged from 0.95 (0.91, 0.97) to 0.47 (0.27, 0.69). The ICC (95% CI) for airway luminal size at functional residual capacity ranged from 0.91 (0.85, 0.95) to 0.32 (0.11, 0.65). The ICC measurements for airway distensibility index and wall thickness were lower, ranging from poor (0.08) to moderate (0.63) agreement. The ICC for air trapping at functional residual capacity was 0.89 (0.81, 0.94) and varied only modestly by lobe from 0.76 (0.61, 0.87) to 0.95 (0.92, 0.97). In stable well-controlled asthmatic subjects, it is possible to reproducibly image unstimulated airway luminal areas over time, by region, and by size at total lung capacity throughout the lungs. Therefore, any changes in luminal size on repeat CT imaging are more likely due to changes in disease state and less likely due to normal variability. There is a surprising lack of studies examining the reproducibility of high-resolution CT in asthma. The current study examined reproducibility of airway measurements. In stable well-controlled asthmatic subjects, it is possible to reproducibly image airway luminal areas over time, by region, and by size at total lung capacity throughout the lungs. Therefore, any changes in luminal size on repeat CT imaging are more likely due to changes in disease state and less likely due to normal variability.
HRCT 研究。123:876-883, 2017. 首次发表于 2017 年 7 月 13 日；doi:10.1152/japplphysiol.00307.2017.-高分辨率 CT（HRCT）是一种成熟的影像学技术，用于在体测量肺部和气道形态。然而，令人惊讶的是，目前很少有研究探讨 HRCT 的可重复性。CPAP 试验是一项多中心、随机、三平行臂、假对照 12 周临床试验，旨在评估夜间持续气道正压通气（CPAP）设备对气道对乙酰甲胆碱反应性的影响。CPAP 对临床或 HRCT 测量无治疗作用，这为当前的分析提供了机会。我们评估了 12 周内 HRCT 成像的可重复性。计算了单个气道节段、单个肺叶、双肺和空气滞留的组内相关系数（ICC）。在总肺活量时气道管腔大小的 ICC（95%置信区间[CI]）范围为 0.95（0.91，0.97）至 0.47（0.27，0.69）。在功能残气量时气道管腔大小的 ICC（95%CI）范围为 0.91（0.85，0.95）至 0.32（0.11，0.65）。气道扩张指数和壁厚度的 ICC 测量值较低，范围从较差（0.08）到中等（0.63）一致。功能残气量时空气滞留的 ICC 为 0.89（0.81，0.94），并且仅略有变化，从 0.76（0.61，0.87）到 0.95（0.92，0.97）。在稳定的、控制良好的哮喘患者中，可以通过区域和整个肺部的总肺活量来重复、可重复地成像未受刺激的气道管腔区域。因此，重复 CT 成像上的管腔大小变化更可能是由于疾病状态的变化，而不太可能是由于正常变异性。目前很少有研究探讨 HRCT 在哮喘中的可重复性。本研究探讨了气道测量的可重复性。在稳定的、控制良好的哮喘患者中，可以通过区域和整个肺部的总肺活量来重复、可重复地成像气道管腔区域。因此，重复 CT 成像上的管腔大小变化更可能是由于疾病状态的变化，而不太可能是由于正常变异性。
