Simultaneous multislice accelerated interleaved EPI DWI using generalized blipped‐CAIPI acquisition and 3D K‐space reconstruction

Purpose Simultaneous multislice (SMS) has been proved to be powerful for accelerating single‐shot echo‐planar imaging (ssh‐EPI) based diffusion‐weighted imaging (DWI), but there are some obstacles for applying SMS to interleaved echo‐planar imaging (iEPI) DWI. The primary challenge is to effectively combine slice unfolding for SMS and intershot phase correction for multishot DWI. In this study, a novel acquisition and reconstruction method for SMS‐accelerated high‐resolution iEPI DWI is proposed. Theory and Methods The traditional blipped‐controlled aliasing in parallel imaging (blipped‐CAIPI) for ssh‐EPI is generalized for iEPI acquisitions. An SMS three‐dimensional (3D) navigator acquisition is designed to record the intershot phase variations. Then, slice unfolding and intershot phase correction are performed simultaneously in an SMS 3D k‐space. The performance of the proposed method is demonstrated in both four‐shot and eight‐shot iEPI DWI and compared with ssh‐EPI and unaccelerated iEPI DWI. Results The proposed method successfully unfolded the simultaneously excited slices and effectively suppressed artifacts from intershot phase variations. The SMS‐accelerated iEPI improved the imaging efficiency, while preserving comparable image quality as unaccelerated iEPI DWI. Conclusions The proposed acquisition and reconstruction is an effective method for accelerating multishot high‐resolution DWI, which may be valuable for both neuroscience research and clinical diagnosis. Magn Reson Med 77:1593–1605, 2017. © 2016 International Society for Magnetic Resonance in Medicine