Fig. 1.
Multiple-pathway model of myocardial tissue region of interest. Cin(t), externally detected vascular input; F, total flow to region of interest; q(t), indicator content of region of interest used to fit experimental indicator content-time curves, as defined excluding a contribution from large vessel content of indicator. N parallel pathways are identical except for flow (fi), representing observed flow heterogeneity. hLV, transfer function of a large conduit vessel between left ventricular blood pool and region of interest; CLV(t), input to all flow pathways; fi, flow in ith pathway; wi, fraction of organ or region of interest having flow fi; hSVi, transfer function of small vessel in ith pathway; hcapi, transfer function for capillary-tissue unit in ith pathway; Cout(t), concentration-time curve in venous outflow.