Abstract

PurposeTo measure both transversal relaxation time (T-2) and diffusion coefficients within a single scan using a multi-shot approach. Both measurements have drawn interest in many applications, especially in skeletal muscle studies, which have short T2 values. Multiple echo single-shot schemes have been proposed to obtain those variables simultaneously within a single scan, resulting in a reduction of the scanning time. However, one problem with those approaches is the associated long echo read-out. Consequently, the minimum achievable echo time tends to be long, limiting the application of these sequences to tissues with relatively long T-2. Materials and MethodsTo address this problem, we propose to extend the multi-echo sequences using a multi-shot approach, so that to allow shorter echo times. A multi-shot dual-echo EPI sequence with diffusion gradients and echo navigators was modified to include independent diffusion gradients in any of the two echoes. ResultsThe multi-shot approach allows us to drastically reduce echo times. Results showed a good agreement for the T-2 and mean diffusivity measurements with gold standard sequences in phantoms and in vivo data of calf muscles from healthy volunteers. ConclusionA fast and accurate method is proposed to measure T-2 and diffusion coefficients simultaneously, tested in vitro and in healthy volunteers. J. Magn. Reson. Imaging 2014;39:1027-1032. (c) 2013 Wiley Periodicals, Inc.