Comparison Between Readout-Segmented (RS)-EPI and an Improved Distortion Correction Method for Short-Axis Propeller (SAP)-EPI

Stefan Skare¹, Samantha J. Holdsworth¹, Kristen Yeom¹, Patrick David Barnes¹, Roland Bammer¹

Short-Axis readout Propeller EPI (SAP-EPI) and Readout-Segmented EPI (RS-EPI) have been proposed for use in high resolution diffusion-weighted (DW) imaging. SAP-EPI and RS-EPI share common characteristics, in that k-space is traversed by several EPI segments in order to reduce the distortion and blurring that typically hampers EPI images. Previous work comparing RS-EPI and SAP-EPI concluded that SAP-EPI suffers from more blurring compared with RS-EPI despite attempts to correct for distortion. With an improved distortion correction method, we demonstrate that SAP-EPI results in similar image resolution to RS-EPI for a given SNR normalized for scan time/slice.