A Paired Phase and Magnitude Reconstruction for Advanced Diffusion-Weighted Imaging

TL;DR

This paper introduces PAIR, a novel reconstruction method for multi-shot diffusion-weighted imaging that effectively reduces ghost artifacts and noise, enabling high-quality images even with many shots and high b-values.

Contribution

The paper proposes an explicit phase model with paired phase and magnitude priors (PAIR) for improved reconstruction in advanced DWI, addressing inter-shot motion and low SNR challenges.

Findings

Successfully removes ghost artifacts in high-shot DWI

Significantly suppresses noise at ultra-high b-values

Demonstrates superior performance in simulations and in vivo tests

Abstract

Objective: Multi-shot interleaved echo planer imaging can obtain diffusion-weighted images (DWI) with high spatial resolution and low distortion, but suffers from ghost artifacts introduced by phase variations between shots. In this work, we aim at solving the challenging reconstructions under inter-shot motions between shots and a low signal-to-noise ratio. Methods: An explicit phase model with paired phase and magnitude priors is proposed to regularize the reconstruction (PAIR). The former prior is derived from the smoothness of the shot phase and enforced with low-rankness in the k-space domain. The latter explores similar edges among multi-b-value and multi-direction DWI with weighted total variation in the image domain. Results: Extensive simulation and in vivo results show that PAIR can remove ghost artifacts very well under a high number of shots (8 shots) and significantly suppress the noise under the ultra-high b-value (4000 s/mm2). Conclusion: The explicit phase model PAIR with complementary priors has a good performance on challenging reconstructions under inter-shot motions between shots and a low signal-to-noise ratio. Significance: PAIR has great potential in advanced clinical DWI applications and brain function research.