3D multi-slab diffusion-weighted readout-segmented EPI with real-time cardiac-reordered K-space acquisition

Area of Science:

• Magnetic Resonance Imaging
• Diffusion Imaging
• Biomedical Engineering

Background:

• Readout-segmented echo-planar imaging (rs-EPI) is crucial for diffusion imaging.
• Motion artifacts, particularly phase artifacts, degrade the quality of diffusion-weighted data.
• Developing 3D imaging techniques is essential for comprehensive volumetric data acquisition.

Purpose of the Study:

• To develop and implement a three-dimensional (3D) extension of the rs-EPI sequence.
• To incorporate real-time cardiac reordering to mitigate motion-induced phase artifacts.
• To demonstrate the feasibility and effectiveness of the 3D rs-EPI sequence for diffusion imaging.

Main Methods:

• Simulations assessed k-space acquisition schemes and motion-induced phase artifacts.
• A cardiac reordering strategy prioritized central k-space acquisition during diastole.
• A 2D navigated multi-slab rs-EPI sequence with real-time cardiac reordering was implemented.

Main Results:

• Cardiac reordering reduced motion-induced phase artifact variability by 30-50% in simulations and in vivo.
• The multi-slab implementation achieved signal-to-noise ratio-optimal repetition times of 1-2 seconds.
• High-resolution diffusion tensor imaging data were successfully acquired using the novel sequence.

Conclusions:

• A 3D multi-slab rs-EPI sequence with cardiac reordering was successfully developed and demonstrated in vivo.
• The developed sequence provides high-quality 3D diffusion-weighted data sets.
• This technique offers a significant advancement for diffusion imaging applications.