Accounting for the heterogeneity of capillary transit times in modeling multiple indicator dilution data
Accounting for the heterogeneity of capillary transit times in modeling multiple indicator dilution data
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DOI：
10.1114/1.138
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发表时间：
1998-11-01
影响因子：
3.8
通讯作者：
Dawson, CA
中科院分区：
文献类型：
--
作者：
Audi, SH;Linehan, JH;Dawson, CA
为了对多指标稀释（MID）数据进行数学建模，以估计指标与组织相互作用的描述参数，有必要考虑毛细管传递时间分布的影响，h(c)(t)。在本文中，我们提出了一种将h(c)(t)纳入MID数据数学建模的有效方法。在该方法中，沿传递时间最长的模型毛细血管在不同位置得到的模型偏微分方程的解提供了所有毛细血管的流出浓度。当用h(c)(t)加权时，这些毛细管流出浓度提供了毛细管床的流出浓度随时间的曲线。无论可用的毛细管弥散数据是根据毛细管传递时间还是相对流量分布，以及弥散是由异质平行路径之间的对流时间差异还是沿单个路径的轴向扩散引起的，该方法都是合适的。最后，我们证明了h(c)(t)的矩之间的关系的知识，而不是h(c)(t)本身，是足够的信息来解释h(c)(t)在MID数据的数学建模解释中的影响。这种关系可以通过在注入的微球中加入限流指示器来确定，从而提供了一种有效的方法来获得足够的实验数据，以解释MID模型中的毛细管流动和传递时间异质性。(C) 1998生物医学工程学会。[s0090 - 6964(98) 01806 - 2]。
To mathematically model multiple indicator dilution (MID) data for the purpose of estimating parameters descriptive of indicator-tissue interactions, it is necessary to account for the effects of the distribution of capillary transit times, h(c)(t). In this paper, we present an efficient approach for incorporating h(c)(t) in the mathematical modeling of MID data. In this method, the solution of the model partial differential equations obtained at different locations along the model capillary having the longest transit time provides the outflow concentrations for ail capillaries. When weighted by h(c)(t), these capillary outflow concentrations provide the outflow concentration versus time curve for the capillary bed. The method is appropriate whether the available data on capillary dispersion are in terms of capillary transit time or relative flow distributions, and whether the dispersion results from convection time differences among heterogeneous parallel pathways or axial diffusion along individual pathways. Finally, we show that the knowledge of a relationship among the moments of h(c)(t), rather than h(c)(t) per se, is sufficient information to account for the effect of h(c)(t) in the mathematical modeling interpretation of MID data. This relationship can be determined by including a flow-limited indicator in the injected bolus, thus providing an efficient means for obtaining the experimental data sufficient to account for capillary flow and transit time heterogeneity in MID modeling. (C) 1998 Biomedical Engineering Society. [S0090-6964(98)01806-2].