To analyze systematic errors and regional variability of the myocardial blood flow (∆MBF) and myocardial perfusion reserve (∆MPR) estimates in dynamic contrast-enhanced perfusion MRI, computational fluid dynamic (CFD)-simulations were performed in a realistic 3D coronary vasculature model of an ex-vivo porcine heart. Simulations were performed down to the pre-arteriolar level for the myocardial segments. The simulations show a strong spatial variance in the resulting ∆MBF and ∆MPR values of up to 60%. The errors are increasing with distance from the model inlet as well as with lower flow velocities. Errors are more pronounced in the right coronary artery.