Estimation of blood flow rates in large microvascular networks based on incomplete boundary conditions

Predicting solute transport properties of microvascular networks requires information on both network structure and the distribution of blood flow. Current methods for imaging microvascular structures provide geometrical data on networks consisting of thousands of segments, but do not allow measurement of flow rates in each segment. Here we present a method for estimating segment blood flow rates based on incomplete flow information in the boundary segments that feed and drain the network. Flow distributions obtained by this method satisfy the governing equations of network flow and minimize the deviation of wall shear stresses from empirically determined values. The method was tested using microvascular networks in the rat mesentery with multiple (20–40) boundary segments. When only two or three boundary conditions were prescribed, the algorithm produced a good estimate of the actual flow distribution obtained when all boundary conditions were prescribed, with high correlation between estimated and actual flows and 10% of the segments having incorrect flow direction. This approach increases the functional information that can be deduced from high‐resolution data on microvascular structure.