The clinical applications of echo planar imaging in neuroradiology

Ultra high speed echo-planar imaging gives an imaging time typically of the order of a few minutes, facilitating throughput, improving patient tolerance and allowing real time dynamic studies. A complete two dimensional image may be acquired in a single shot lasting between 64 and 128 ms. In echo planar imaging the whole of k-space is sampled as a continuous trajectory. By a rapidly switched Gy frequency encoding gradient, a train of gradient echoes is formed, each corresponding to a line in the k plane. Variable degrees at T2- or T1-weighting can be produced by methods outlined. High quality 128 x 128 transverse axial inversion recovery images of 5-10 mm thickness are obtained in 128 ms plus the inversion time.