Fast Spin-Echo Imaging of Inner Field-of-Views Using 2D-Selective RF Excitations

Introduction Image blurring due to the signal decay along the echo train as well as the RF energy deposited by the refocusing RF pulses limit the applicability of high turbo factors, i.e. a large number of echoes per shot, in fast spin-echo imaging [1], in particular at higher static magnetic fields. In this work, 2D-selective RF (2DRF) excitations [2,3]are used to focus the field-of-view (FOV) to a small inner volume without aliasing in the phase-encoding direction. This reduces the image blurring as the k-space velocity in the phase-encoding direction can be increased but also reduces the number of echoes required and thus the acquisition time and the RF deposited. This is demonstrated in phantoms and the human brain at 3T where even in single-shot acquisitions high in-plane resolutions could be realized.