Short‐TR, Coherent, Gradient Echo Imaging

Abstract When a spin system is repeatedly disturbed by a fast repetition of RF pulses, the transverse magnetization after each new RF pulse approaches a steady‐state value which is smaller than the thermal equilibrium value. The spin system takes a finite number of pulses before this steady‐state is reached in a time that depends on both the T1 of the tissue and the flip angle of the RF pulse. The focus of this unit is on understanding the build‐up of the magnetization to steady‐state and the practical implementation of the simplest forms of imaging in the steady‐state. Sequences utilizing a steady‐state approach can be broadly classified as steady‐state coherent (SSC) and steady‐state incoherent (SSI) sequences. The SSC behavior is the subject of this unit.