Robust Self-Calibrating nCPMG Acquisition: Application to Body Diffusion-Weighted Imaging.

Area of Science:

• Magnetic Resonance Imaging
• Diffusion-Weighted Imaging
• Pulse Sequence Design

Background:

• Off-resonance conditions challenge diffusion-weighted single-shot fast spin echo (SS-FSE) imaging.
• Non-Carr-Purcell-Meiboom-Gill (nCPMG) SS-FSE stabilizes echo families but can cause aliasing.
• Existing methods struggle with reconstruction complexity and motion artifacts.

Purpose of the Study:

• To develop a robust SS-FSE sequence for diffusion-weighted imaging under significant off-resonance.
• To improve scan efficiency and motion robustness in nCPMG SS-FSE acquisitions.
• To present a novel self-calibrated reconstruction for enhanced nCPMG SS-FSE imaging.

Main Methods:

• Implemented a variable-density k-space acquisition strategy to improve scan efficiency.
• Developed a self-calibrated reconstruction method to address quadrature component aliasing.
• Validated the technique using phantom studies and in vivo abdominal imaging in healthy volunteers and patients.

Main Results:

• The new approach demonstrated comparable signal-to-noise ratio (SNR) to previous nCPMG techniques.
• Phantom scans showed more uniform apparent diffusion coefficient (ADC) maps.
• In vivo scans indicated improved robustness against motion artifacts.

Conclusions:

• The proposed nCPMG SS-FSE acquisition and reconstruction method offers enhanced robustness and efficiency.
• This technique provides accurate and uniform ADC quantification, particularly in abdominal imaging.
• The self-calibrated reconstruction effectively handles signal complexities, improving clinical applicability.