Fig. 1
Schematic overview of the T2 preparation mechanism. A 90º radiofrequency (RF) pulse creates transverse magnetization that immediately starts decaying with a rate determined by the tissue-dependent T2 relaxation time. One or more 180º refocusing RF pulses are used to reduce signal dephasing caused by magnetic field inhomogeneities. After the effective echo time (TEeff), a -90º ‘tip-up’ RF pulse tips the remaining Mxy back towards the longitudinal axis, where the magnetization is stored again as Mz. As the blood pool has a longer T2 relaxation time than scar tissue, the Mz blood will be higher than that of myocardium directly after T2 preparation (white rectangle)