Beinert T, Behr J, Mehnert F, Kohz P, Seemann M, Reiser M
Universität München, Klinikum Grosshadern, Medizinische Klinik I, Abteilung für Pneumologie.
Pneumologie. 1995 Dec;49(12):678-83.
Computed tomography provides measurements of lung attenuation which reflect changes in the air to tissue ratio and can thereby be employed for diagnosis of diffuse lung disease. In this prospective study, we quantitatively analyzed lung density by high resolution computed tomography (HRCT) in 26 healthy volunteers, 15 patients with chronic obstructive pulmonary disease (COPD), and 15 patients with idiopathic lung fibrosis (IPF). The procedure was standardized by examination of 3 scans at the carina +/- 5 cm and by defining inflation levels by %VC using an on-line hand held spirometer.
Performance of HRCT at 50% VC provides not only significant and distinguishable group data, but is the easiest to carry out for dyspneic patients. The mean lung density at 50% VC for healthy subjects was -820 +/- 4.2 (mean +/- SEM) Hounsfield units (HU). It was significantly lower (p < 0.01) in COPD patients (-865 +/- 9.2 HU), and considerably higher (-697 +/- 17.8 HU, p < 0.001) in the IPF group. At an inflation level of 20% VC, mean lung density values were similarly distributed, at significantly lower values relative to those at 50% VC, but the procedure was more difficult to perform for patients with dyspnea. In contrast, at 80% VC, lung density values for the COPD and control groups were not significantly different (p = 0.08). The sensitivity to detect COPD was improved by selecting HRCT values lower than -900 HU, which represent the part of the lung with an increased air/tissue ratio. For IPF patients an increase of lung density values above -699 HU was characteristic, indicating a decrease of the air/tissue relationship.
From our data we propose to perform quantitative HRCT measurements at 50% VC. Diagnosis of diffuse lung disease can be further improved by consideration of specific CT -value intervals. Spirometrically controlled quantitative HRCT is a clinically meaningful tool for the assessment of diffuse parenchymal lung disease.
计算机断层扫描可测量肺衰减，反映空气与组织比例的变化，从而用于诊断弥漫性肺疾病。在这项前瞻性研究中，我们通过高分辨率计算机断层扫描（HRCT）对26名健康志愿者、15名慢性阻塞性肺疾病（COPD）患者和15名特发性肺纤维化（IPF）患者的肺密度进行了定量分析。该程序通过在隆突±5 cm处进行3次扫描检查，并使用在线手持式肺活量计以%VC定义充气水平来标准化。
在50% VC时进行HRCT不仅能提供显著且可区分的组间数据，而且对呼吸困难患者来说是最容易实施的。健康受试者在50% VC时的平均肺密度为-820±4.2（平均值±标准误）亨氏单位（HU）。COPD患者的该值显著更低（p < 0.01）（-865±9.2 HU），而IPF组则显著更高（-697±17.8 HU，p < 0.001）。在20% VC的充气水平下，平均肺密度值的分布类似，相对于50% VC时的值显著更低，但该程序对呼吸困难患者来说更难实施。相反，在80% VC时，COPD组和对照组的肺密度值无显著差异（p = 0.08）。通过选择低于-900 HU的HRCT值来检测COPD的敏感性得到了提高，该值代表肺中空气/组织比例增加的部分。对于IPF患者，肺密度值高于-699 HU是其特征，表明空气/组织关系降低。
根据我们的数据，我们建议在50% VC时进行定量HRCT测量。通过考虑特定的CT值区间，可进一步改善弥漫性肺疾病的诊断。肺活量计控制的定量HRCT是评估弥漫性实质性肺疾病的一种具有临床意义的工具。
