Parallel EPI artifact correction (PEAC) for N/2 ghost suppression in neuroimaging applications

Area of Science:

• Neuroimaging
• Medical Physics
• Biomedical Engineering

Background:

• Echo Planar Imaging (EPI) is crucial for clinical and research neuroimaging.
• EPI is prone to Nyquist N/2 ghost artifacts caused by phase inconsistencies.
• Current artifact correction methods require a reference scan, limiting performance due to motion sensitivity.

Purpose of the Study:

• To introduce a novel, reference-less EPI data processing technique: Parallel EPI Artifact Correction (PEAC).
• To enable improved neuroimaging performance by overcoming limitations of motion-sensitive artifact correction.
• To demonstrate PEAC's effectiveness in suppressing ghost artifacts and handling dynamic motion.

Main Methods:

• Developed PEAC, a technique leveraging multi-coil sensitivity in parallel imaging as an implicit data constraint.
• Formulated phase correction as a constrained problem solvable by an iterative algorithm.
• Applied and evaluated PEAC on a standard functional magnetic resonance imaging (fMRI) protocol using multi-slice 2D EPI.

Main Results:

• PEAC effectively suppresses ghost artifacts, performing comparably to standard reference-scan based techniques.
• The method enables dynamic phase correction, adapting to subject motion during scanning.
• PEAC provides a viable alternative for artifact correction in EPI, particularly in motion-prone scenarios.

Conclusions:

• PEAC offers a robust, reference-less solution for mitigating EPI ghost artifacts.
• This technique enhances the utility of EPI in neuroimaging applications by improving motion robustness.
• PEAC represents a significant advancement for high-quality functional MRI and other EPI-based investigations.