Gould G A, Redpath A T, Ryan M, Warren P M, Best J J, Flenley D C, MacNee W
Dept. of Respiratory Medicine, City Hospital, Edinburgh, Scotland.
Eur Respir J. 1991 Feb;4(2):141-6.
We studied 80 subjects (63 M, 17 F; 23-82 yrs) and related lung computerized tomography (CT) density with age, height, spirometry, lung volumes, diffusing capacity and arterial blood gas tensions. These subjects demonstrated a wide range of physiological impairment (forced expiratory volume in one second (FEV1) 8-116% predicted; diffusing capacity (Kco) 15-139% predicted; arterial oxygen tension (Pao2) 38-91 mmHg). They ranged from normal subjects to patients with chronic respiratory failure. Lung density was derived from CT density histograms measured as both mean Emergency Medical Information (EMI) number (EMI scale: 0 = water, -500 = air, EMI number of normal lung tissue range approximately -200 to -450) and the lowest 5th percentile EMI number, the latter value being more likely to represent the density of lung parenchyma. Lung CT density correlated most strongly with airflow obstruction (EMI 5th percentile versus FEV1/forced vital capacity (FVC) % predicted, r = 0.73, p less than 0.001) and diffusing capacity (EMI 5th percentile versus Kco, r = 0.77, p less than 0.001). This suggests that reduction in lung density, which reflects loss of the surface area of the distal airspaces, is a major index of respiratory function in patients with smoking related chronic obstructive pulmonary disease (COPD). These data provide no indication of other factors such as small and large airways disease, and loss of elastic recoil, which may contribute to airflow limitation, or disruption of the pulmonary vascular bed which may also affect CT lung density.
我们研究了80名受试者（男性63名，女性17名；年龄23 - 82岁），并将肺部计算机断层扫描（CT）密度与年龄、身高、肺量计、肺容积、弥散能力及动脉血气张力进行关联分析。这些受试者表现出广泛的生理功能损害（一秒用力呼气容积（FEV1）为预测值的8% - 116%；弥散能力（Kco）为预测值的15% - 139%；动脉血氧张力（Pao2）为38 - 91 mmHg）。他们涵盖了从正常受试者到慢性呼吸衰竭患者的范围。肺密度源自CT密度直方图，通过平均急诊医疗信息（EMI）值（EMI量表：0 = 水，-500 = 空气，正常肺组织的EMI值范围约为 - 200至 - 450）以及最低的第5百分位数EMI值来测量，后者更有可能代表肺实质的密度。肺CT密度与气流阻塞（EMI第5百分位数与预测的FEV1/用力肺活量（FVC）%，r = 0.73，p < 0.001）和弥散能力（EMI第5百分位数与Kco，r = 0.77，p < 0.001）的相关性最强。这表明反映远端气腔表面积丧失的肺密度降低是吸烟相关慢性阻塞性肺疾病（COPD）患者呼吸功能的主要指标。这些数据未显示其他因素的迹象，如大小气道疾病、弹性回缩丧失（可能导致气流受限）或肺血管床破坏（也可能影响CT肺密度）。
