VUDU-SAGE: Efficient T2 and T2* Mapping using Joint Reconstruction for Motion-Robust, Distortion-Free, Multi-Shot, Multi-Echo EPI

We demonstrate T2 and T2* mapping and joint reconstruction for multi-echo, multi-shot EPI data from a variable flip angle, blip-up and -down undersampling (VUDU) for spin and gradient echo (SAGE) acquisition. VUDU-SAGE employs a blip-up and -down acquisition strategy for correcting B0 distortion, and FLEET-ordering for motion-robust multi-shot EPI while maximizing signal using variable flip angles. VUDU-SAGE acquires five echoes consisting of two gradient-echo, two mixed, and one spin-echo contrasts. We jointly reconstruct all echoes and estimate T2 and T2* maps using Bloch dictionary matching. In-vivo experiment presents T2 and T2* map at 1x1x4mm3 resolution with a 9-second acquisition.