A new MRI imaging sequence, the Septal Scout, has been presented. This new technique can accurately determine the timing of diastasis windows for the purpose of cardiac gating in applications such as high-resolution coronary MRA. The Septal Scout acquires 1D MR images along the long-axis of the basal ventricular septum either through projection imaging or 2D excitations. Each acquisition produces a line of data along the ventricular septum. The acquisition is repeated over time to generate a time-map of Septal Scouts. The data from the Septal Scout time-map is processed to generate a velocity graph of an ROI near the basal septum. From this graph, the beginning and end of diastasis is determined. This timing information is available for use to facilitate cardiac gating in subsequent high-resolution MR angiography.