Reduced Field of View Imaging for Twice-Refocused Diffusion EPI Using a Perpendicular Refocusing Slab

Rafael Luis O'Halloran¹, Samantha J. Holdsworth¹, Stefan Skare¹, Roland Bammer¹

A simple method for reducing the phase field of view in twice-refocused DTI EPI is presented and compared with full of view imaging in DTI of the upper spine. The 180-degree refocusing slice select pulses are played out on the phase encoding axis instead of the slice-encoding axis. This allows the phase field of view to be reduced to the width of the perpendicular refocusing slab without introducing wrap. Results show that the reduced field of view method produces diffusion weighted images of the cervical and thoracic spine that are less distorted than those of standard full field of view EPI for the same scan time.