Body diffusion-weighted imaging using magnetization prepared single-shot fast spin echo and extended parallel imaging...

Area of Science:

• Magnetic Resonance Imaging
• Medical Physics
• Biomedical Engineering

Background:

• Diffusion-weighted imaging (DWI) is crucial for visualizing tissue microstructure.
• Conventional DWI sequences, like echo-planar imaging (EPI), are susceptible to geometric distortions, especially in body imaging.
• Fast spin echo (FSE) sequences offer better distortion robustness but traditionally lack efficient diffusion weighting.

Purpose of the Study:

• To develop and validate a magnetization-prepared diffusion-weighted single-shot fast spin echo (SS-FSE) sequence for body imaging.
• To enhance robustness against geometric distortion and artifacts caused by object phase.
• To introduce an improved scan averaging technique for better image quality.

Main Methods:

• A novel SS-FSE pulse sequence was designed, incorporating magnetization preparation for diffusion weighting.
• The sequence ensures robustness against violations of the Carr-Purcell-Meiboom-Gill (CPMG) condition by dephasing and spoiling specific signal components.
• Extended Parallel Imaging (ExtPI) averaging with SVD-based coil compression was employed for reconstruction and noise suppression.

Main Results:

• Simulations confirmed stable signal generation and good image quality throughout the echo train.
• The proposed Extended Parallel Imaging (ExtPI) reconstruction effectively recovered signal-to-noise ratio (SNR).
• In vivo abdominal scans demonstrated successful diffusion-encoded imaging with significantly mitigated geometric distortion compared to EPI.

Conclusions:

• The developed diffusion-prepared SS-FSE sequence provides robust diffusion contrast in clinical settings.
• The sequence effectively addresses geometric distortion artifacts common in body imaging.
• The proposed method offers a valuable alternative for diffusion imaging in challenging anatomical regions.