Improper selection of Start of Myocardial Enhancement (SME) can lead to significant errors in Myocardial Blood Flow (MBF) quantification. The average MBF is plotted against the time shift before and after the reference start time. MBF is minimally affected by shifting the SME earlier than the reference. However, when the SME is shifted after the reference, the MBF was significantly overestimated. The * represents MBF that is significantly (p < 0.05) different from the reference MBF.