Motion correction for functional MRI with three-dimensional hybrid radial-Cartesian EPI

Area of Science:

• Magnetic Resonance Imaging
• Neuroimaging
• Biomedical Engineering

Background:

• Subject motion is a primary cause of image degradation in functional MRI (fMRI), particularly with multishot sequences like 3D EPI.
• This degradation significantly impacts the reliability and accuracy of fMRI studies.

Purpose of the Study:

• To introduce and evaluate a novel hybrid radial-Cartesian 3D EPI trajectory for motion correction in fMRI.
• To enable robust motion correction directly in k-space during image reconstruction.

Main Methods:

• The TURBINE sequence utilizes a hybrid radial-Cartesian trajectory with rotating EPI "blades" to fill 3D k-space.
• Golden-angle increments allow flexible temporal resolution, and self-navigating properties provide motion parameters.
• Motion is corrected in k-space during image reconstruction, tested with cued and natural motion paradigms.

Main Results:

• The developed motion correction technique demonstrates robust performance across various motion severities.
• Substantial reduction in image artifacts was achieved.
• Significant improvements in temporal signal-to-noise ratio and fMRI activation were observed.

Conclusions:

• The hybrid radial-Cartesian 3D EPI approach effectively mitigates motion artifacts in fMRI.
• This method is particularly beneficial for patient groups experiencing significant head motion.
• The technique requires no additional scan time or hardware, making it practical for widespread fMRI applications.