Electromechanical analysis of optimal trigger delays for cardiac MRI

Background Single-phase cardiac MRI acquires data only during a brief period of the cardiac cycle. To avoid motion artifacts, the operator must select a trigger delay that corresponds to a period of minimal cardiac motion, typically at end-systole or mid-diastole. This can be done by inspecting a prior cine scan for quiescent periods. However, because these cardiac phases can vary in temporal position and duration as a function of heart rate, another option should be available if the heart rate at the time of the single-phase scan differs from that during the cine scan. The goal of this work was to analytically determine the optimal trigger delays for cardiac MRI.