Measurements of regional ventilation pulmonary gas volume: theory and error analysis with special reference to positron emission tomography.
Measurements of regional ventilation pulmonary gas volume: theory and error analysis with special reference to positron emission tomography.
复制标题
区域通气肺气体量的测量：理论和误差分析，特别参考正电子发射断层扫描。
作者：
S. Valind;Christopher G. Rhodes;L. Brudin;T. Jones
基于短寿命放射性核素19 Ne（T1/2 = 17.4秒）的用于测量肺泡通气的稳态技术对PET的适应允许在明确定义的几何条件下以定量方式分析稳态肺模型。区域气体体积是必不可少的，这种分析，和区域测量的肺气体体积的基础上，透射断层扫描，并在本文中进行了验证。稳态方法的准确性在很大程度上取决于用于描述示踪剂在肺中传输的肺模型的有效性。本研究考虑了单个肺区域内的示踪剂运输和混合。血流和肺泡-毛细血管气体交换不会显著影响所获得的值，即使在通气/灌注比高度异常的区域也不会。一个不均匀的区域内的气流分布的结果在低估的区域通气，由该区域内的肺泡气体的呼吸周转率的分散确定。在正常肺中，这种低估可以忽略不计。在疾病中，几乎不通气的单位和正常工作的单位的分辨率体积内的混合可能导致肺泡通气的低估高达60%。
The adaptation to PET of the steady-state technique for the measurement of alveolar ventilation, based on the short-lived radionuclide 19Ne (T1/2 = 17.4 sec), allows the steady-state lung model to be analyzed in a quantitative way under well-defined geometrical conditions. The regional gas volume is essential to this analysis, and regional measurements of the pulmonary gas volume based on transmission tomography are presented and validated in this paper. The accuracy of the steady-state method rests largely with the validity of the lung model applied to describe the transport of tracer in the lung. This study considers tracer transport and mixing within individual lung regions. Blood flow and the alveolar-to-capillary exchange of gases do not significantly affect the values obtained, not even in regions with highly abnormal ventilation/perfusion ratios. A nonuniform intra-regional gas flow distribution results in an underestimation of the regional ventilation, determined by the dispersion of the ventilatory turnover rates of alveolar gas within the region. In the normal lung this underestimation is negligible. In disease, a mixing within the resolution volume of units that are almost non-ventilated and units that perform normally may result in an underestimation of alveolar ventilation by up to 60%.