Myocardial delayed enhancement imaging must regulate inversion time (TI) so that the signal intensity of the normal myocardium becomes null, and look-locker imaging is performed prior to myocardial delayed enhancement imaging to determine the optimal TI. We think that the null point measured by look-locker imaging may change with the adjustment of some imaging parameters like the IR-T(1)TFE sequence used in myocardial delayed enhancement imaging. Therefore, the purpose of this study is to examine the change of the null point with the adjustment of some imaging parameters for look-locker imaging and to study factors affecting the consistency of the null point with the IR-T(1)TFE sequence. The null point of both sequences of look-locker imaging and the IR-T(1)TFE sequence changed with the RR interval and with the number, FA, and interval of RF pulses applied within the RR interval. To match the null points in both sequences, it is necessary to make the RR intervals the same and to match the number, FA, and interval of RF pulses applied to within 1 heartbeat.