Slice-POCS-ICE: a navigator-free reconstruction for SMS-accelerated multi-shot spiral-based diffusion-weighted imaging

Motivation: Simultaneous multi-slice (SMS) technique can further enhance the acquisition efficiency of spiral-based diffusion imaging. Goal(s): Our goal was to achieve SMS-accelerated navigator-free multi-shot spiral-based diffusion imaging. Approach: RF pulse phase encoding strategy was optimized to introduce the CAIPI phase modulation. Furthermore, we proposed the slice-POCS-ICE algorithm to simultaneously perform CAIPI phase demodulation, inter-shot phase error correction, and diffusion image reconstruction. The proposed algorithm was tested on simulated and in-vivo data. Results: Our proposed slice-POCS-ICE algorithm can simultaneously accomplish CAIPI phase demodulation and remove the shot-to-shot phase variations, for SMS-accelerated multi-shot navigator-free spiral-based DWI. The proposed slice-POCS-ICE has a stable convergence behavior. Impact: The proposed slice-POCS-ICE reconstruction algorithm can successfully reconstruct multi-shot diffusion images from SMS-accelerated navigator-free spiral acquisitions with optimized CAIPI phase modulation, which may be valuable for speeding up multi-shot spiral-based DWI acquisitions, to facilitate both neuroscience research and clinical diagnosis.