Implementation and assessment of diffusion-weighted partial Fourier readout-segmented echo-planar imaging.

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Diffusion Tensor Imaging (DTI)

Background:

• Single-shot echo-planar imaging (EPI) is widely used in diffusion MRI due to challenges in correcting motion artifacts in multishot data.
• Readout-segmented EPI improves multishot data by using nonlinear navigator correction, reducing artifacts and T*(2) blurring for high-resolution diffusion imaging.

Purpose of the Study:

• To investigate methods for reducing the long acquisition time of readout-segmented EPI.
• To evaluate the impact of partial Fourier reconstruction techniques on diffusion MRI data quality and accuracy.

Main Methods:

• Compared homodyne and projection onto convex sets (POCS) reconstructions for partial Fourier accelerated readout-segmented EPI.
• Assessed effects on fractional anisotropy, mean diffusivity, diffusion orientation, and signal-to-noise ratio.
• Utilized varying segment numbers for different diffusion tensor image resolutions.

Main Results:

• Projection onto convex sets (POCS) reconstruction demonstrated good fidelity to full k-space data.
• Effective acceleration achieved with 3/5 segments for 2 mm isotropic DTI and 9/13 segments for 0.9 × 0.9 × 4.0 mm³ diffusion-weighted imaging.
• Signal-to-noise ratio was maintained effectively with POCS reconstruction.

Conclusions:

• Partial Fourier reconstruction significantly reduces readout-segmented EPI acquisition time without compromising data integrity.
• Accelerated readout-segmented EPI is suitable for diffusion tensor imaging, enabling applications in tractography, stroke, and oncology imaging.