Simultaneous Multi-Slice Diffusion Imaging using Navigator-free Multishot Spiral Acquisition

TL;DR

This paper introduces a novel navigator-free multiband multishot spiral acquisition and a new reconstruction algorithm, slice-POCS-ICE, to improve high-resolution diffusion imaging by effectively resolving phase errors and artifacts.

Contribution

It presents a new acquisition scheme and a reconstruction algorithm that together enable high-efficiency, high-resolution diffusion imaging without the need for navigators.

Findings

Slice-POCS-ICE accurately estimates phase variations.

The method reduces artifacts and improves image quality.

Effective in both simulations and in vivo experiments.

Abstract

Purpose: This work aims to raise a novel design for navigator-free multiband (MB) multishot uniform-density spiral (UDS) acquisition and reconstruction, and to demonstrate its utility for high-efficiency, high-resolution diffusion imaging. Theory and Methods: Our design focuses on the acquisition and reconstruction of navigator-free MB multishot UDS diffusion imaging. For acquisition, radiofrequency (RF) pulse encoding was employed to achieve Controlled Aliasing in Parallel Imaging (CAIPI) in MB imaging. For reconstruction, a new algorithm named slice-POCS-enhanced Inherent Correction of phase Errors (slice-POCS-ICE) was proposed to simultaneously estimate diffusion-weighted images and inter-shot phase variations for each slice. The efficacy of the proposed methods was evaluated in both numerical simulation and in vivo experiments. Results: In both numerical simulation and in vivo experiments, slice-POCS-ICE estimated phase variations more precisely and provided results with better image quality than other methods. The inter-shot phase variations and MB slice aliasing artifacts were simultaneously resolved using the proposed slice-POCS-ICE algorithm. Conclusion: The proposed navigator-free MB multishot UDS acquisition and reconstruction method is an effective solution for high-efficiency, high-resolution diffusion imaging.