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

Area of Science:

• Magnetic Resonance Imaging
• Image Reconstruction
• Diffusion-Weighted Imaging

Background:

• Multi-shot interleaved echo planar imaging (Ms-iEPI) offers high-resolution, low-distortion diffusion-weighted images (DWI).
• Ms-iEPI is susceptible to ghost artifacts from inter-shot phase variations, limiting its clinical utility.
• Reconstructing Ms-iEPI DWI at ultra-high b-values exacerbates noise and artifacts.

Purpose of the Study:

• To develop a robust method for reconstructing Ms-iEPI DWI data corrupted by inter-shot motion and ultra-high b-values.
• To address the challenges of ghost artifacts and low signal-to-noise ratio in advanced DWI applications.

Main Methods:

• Proposed an iteratively joint estimation model named PAIR (Phase and Magnitude Priors).
• Utilized low-rankness in k-space for phase prior and weighted total variation in image space for magnitude prior.
• Transferred edge information from b=0 images to DWI reconstructions for noise suppression and edge preservation.

Main Results:

• PAIR effectively removed inter-shot motion artifacts in 8-shot data.
• Demonstrated significant noise suppression under ultra-high b-values (4000 s/mm²).
• Showcased strong performance on simulated and in vivo data.

Conclusions:

• The PAIR model successfully reconstructs challenging Ms-iEPI DWI data with inter-shot motions and low SNR.
• PAIR offers a promising solution for advanced clinical DWI and microstructure research.