Echo-planar imaging

This paper demonstrates state-of-the-art echo-planar imaging (EPI) and its potential as a diagnostic modality. EPI provides 128 x 128- and 256 x 128-pixel MR images in 64 or 128 msec. The module structure of EPI, with separate spin-parameter encoding and image acquisition, allows flexible pulse sequence tailoring and interactive scanning with real-time feedback. We report the experience we have gained in over 200 EPI studies of head and body in adult and pediatric patients as well as fetuses in utero. EPI provides resolution in the millimeter range, T1 and T2 contrast, and dynamic morphologic as well as functional information. Parameters, including flow, perfusion, and relaxation, can be quantified in seconds. EPI can provide functional and morphologic information in a single examination, which is particularly useful in studies of cardiac dynamics, blood and cerebrospinal fluid flow, brain perfusion, and the GI tract