“Gold standard” oxygen consumption (x-axis) calculated from blood gas and blood flow measurements versus oxygen consumption calculated from the parameter estimates derived with the LIPSSS method (y- axis). Each data point corresponds to one heart. The line of identity is plotted in black. Error bars correspond to the standard error of the mean of the oxygen consumption based on NMR measurements over all samples taken from one heart. Note that the error for blood-gas measurements using radioactive microspheres to measure local blood flow is estimated to be about 9% accounting for measurement error, spatial and temporal variation.