Diffusion-weighted PROPELLER with a novel unaliasing technique for small Field of View imaging

Diffusion-weighted (DW) imaging is widely used in clinical imaging. To address the strong distortion encountered in EPI-based DW techniques, split-blade DW-PROPELLER [1] was proposed. With PROPELLER, when imaging a small Field of View (FOV) of a large object, No-Phase-Wrap (NPW) is usually applied to remove aliased signal in each blade before combining them [2]. However, with this conventional NPW [2], the blade width, already very narrow in DW-PROPELLER, is further reduced. This not only increases scan time, but also makes it more vulnerable to motion. Recently an innovative parallel imaging technique called mutual calibration [3] was introduced for DW-PROPELLER. In this work, we propose a new method based on this technique to achieve the same goal as conventional NPW, without sacrificing the blade width or scan time. Phantom and in vivo DW spine images suggest this is a promising alternative to conventional NPW.