Gradient Echo

Principles and concepts of gradient echo (GRE) imaging are the basis of many applications on modern MR-systems. The most obvious difference between Spin Echo and GRE imaging is related to the pulse sequence elements that are used to generate an MR signal (see figure 1). While two rf-pulses (90 and 180) are used for spin refocusing and spin echo generation, GRE imaging is based on only a single rf-pulse, typically < 90, in combination with read gradient reversal. As a result shorter repetition times (TR) and therefore faster imaging is feasible. Although signal formation is also more sensitive to field homogeneity and gradient performance, today's advanced hardware permits the successful application of GRE imaging with reliable and reproducible image quality. Many GRE based applications such as dynamic cardiac imaging or MR angiography are an integral part of MR protocols used in routine clinical settings.