Nopp P, Harris N D, Zhao T X, Brown B H
Department of Medical Physics, Royal Hallamshire Hospital, Sheffield, UK.
Med Biol Eng Comput. 1997 Nov;35(6):695-702. doi: 10.1007/BF02510980.
Electrical impedance tomographic spectroscopy measurements of the lungs are taken from nine normal subjects, in the frequency range 9.6 kHz-1.2 MHz. The results show that resistivity rho'FRC relative to functional residual capacity increases almost linearly with inspiration volume V, with the slope of the curve increasing with frequency f. Resistivity rho'9.6 kHz relative to 9.6 kHz decreases with f. rho'9.6 kHz increases with V, at any given frequency. Curves for rho'9.6 kHz show a roughly linear trend with log10(f). Based on a discussion of the measurement results, a mathematical lung tissue model is designed that involves extra-capillary blood vessels and alveoli, the walls of which consist of blood-filled capillaries, epithelial cells and intercellular liquid. Using this model, the increase in rho'FRC with V is explained by the thinning of alveolar walls with increasing air content. The almost linear shape of curves for rho'9.6 kHz is attributed to four partly overlapping main dispersions caused by extra-capillary blood vessels, epithelial cells, blood and the capillary network.
对9名正常受试者在9.6千赫至1.2兆赫频率范围内进行了肺部电阻抗断层光谱测量。结果表明，相对于功能残气量的电阻率ρ'FRC随吸气量V几乎呈线性增加，曲线斜率随频率f增加。相对于9.6千赫的电阻率ρ'9.6千赫随f降低。在任何给定频率下，ρ'9.6千赫随V增加。ρ'9.6千赫的曲线与log10(f)呈现大致线性趋势。基于对测量结果的讨论，设计了一个数学肺组织模型，该模型涉及肺外血管和肺泡，其壁由充满血液的毛细血管、上皮细胞和细胞间液组成。使用该模型，ρ'FRC随V的增加可通过肺泡壁随着空气含量增加而变薄来解释。ρ'9.6千赫曲线的近似线性形状归因于由肺外血管、上皮细胞、血液和毛细血管网络引起的四个部分重叠的主要色散。
