title: Estimation of sinusoidal flow heterogeneity in normal and diseased rat livers from tracer dilution data using a fractal model.
abstract: OBJECTIVE
  Up to now, vascular indicator-dilution curves have been analyzed by numerical integration or by fitting empirical functions to the data. Here, we apply a recently developed mechanistic model with the goal to quantitatively describe flow distribution in the sinusoidal network of normal rat livers and those with high-fat emulsion-induced NASH.
  
  
  METHODS
  Single-pass outflow concentration data of sucrose were obtained from in situ perfused rat livers after impulse injection. The model fitted to the data consists of a continuous mixture of inverse Gaussian densities assuming a normal distribution of regional flow. It accounts for the fractal flow heterogeneity in the organ and has three adjustable parameters with a clear physiological interpretation.
  
  
  RESULTS
  The model fitted the data well and revealed that the intrahepatic flow dispersion of 49.6 % in the control group increased significantly to 87.2 % in the NASH group (p < 0.01). In contrast to previously used empirical functions, the present model exhibits a power-law tail (~t(-2.4)), which is a signature of fractal microvascular networks.
  
  
  CONCLUSIONS
  The approach offers the possibility to determine hepatic blood flow heterogeneity in perfused livers and to evaluate the functional implications.
authors: Department of Pharmacology, Martin Luther University Halle-Wittenberg, Halle, Germany. michael.weiss@medizin.uni-halle.de
authors: Michael
authors: M
authors: Weiss
authors: Peng
authors: P
authors: Li
authors: Michael S
authors: MS
authors: Roberts
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity; D008099:Liver / Q000098:blood supply*; D008107:Liver Diseases / Q000503:physiopathology*; D008955:Models, Cardiovascular; D010477:Perfusion; D051381:Rats