SIR-EPI Diffusion Imaging for 3-Fold Faster Scan Time to Enable Trade-Offs in Slice Coverage and Gradient Duty Cycle Reduction.

Sudhir Ramanna¹, Vibhas Deshpande², David Feinberg^1,3

The use of high b-values encoded with lengthy high amplitude gradient pulses place limitations on diffusion imaging with HARDI techniques. In this work, we develop and evaluate SIR with two and three echoes per read period (SIR-2, SIR-3) for HARDI imaging. Both SIR-2 and SIR-3 EPI sequences are shown to be useful for simply reducing scan time, for obtaining higher resolution or field of view on the slice axis with more slices per TR or instead controlling the heat limitations using high b-values by reducing the gradient duty cycle in HARDI acquisitions.