This study explores use of whole-body CT imaging to separately quantitate the physiological behavior of the nonrecruitable (e.g., arterioles) and recruitable (mostly capillary) components of the intramyocardial microcirculation. In two groups of dogs, one with microembolization and one with epicardial artery stenosis, we demonstrate that intramyocardial blood volume (rho) and blood flow (F) follow the relationship rho = AF + BF1/2 where A represents the transit time of the recruitable and BF-1/2 is the transit time of the nonrecruitable components. These transit times are shown to change in different, but characteristic, patterns.