Prospective motion correction for diffusion weighted EPI of the brain using an optical markerless tracker

Area of Science:

• Neuroimaging
• Medical Physics
• Biomedical Engineering

Background:

• Diffusion-weighted imaging (DWI) is crucial for brain studies but sensitive to motion.
• Existing motion correction methods can be cumbersome or require patient cooperation.

Purpose of the Study:

• To develop and evaluate a motion-robust technique for brain DWI.
• To enable high-quality imaging despite subject movement using established methods.

Main Methods:

• Utilized an optical markerless tracking system for real-time head motion estimation and correction.
• Employed single-shot Echo Planar Imaging (EPI) with GRAPPA acceleration and motion-robust calibration.
• Implemented Full Fourier imaging to mitigate motion during diffusion encoding.

Main Results:

• Prospective motion correction (PMC) with dynamic ghost correction yielded high-quality DWI with up to 10° motion.
• PMC did not degrade images acquired without motion.
• Diffusion tensor calculations were robust, though apparent diffusion coefficient (ADC) values showed a slight increase.

Conclusions:

• Markerless optical tracking-based PMC is effective for EPI-based DWI.
• This method is suitable for patient groups unable to remain still or comply with markers.
• Minimizes patient interaction, enhancing usability in clinical settings.