Three dimensional radial echo planar imaging for functional MRI.

Area of Science:

• Magnetic Resonance Imaging
• Neuroimaging
• Functional Magnetic Resonance Imaging (fMRI)

Background:

• Functional MRI (fMRI) is crucial for understanding brain activity.
• Current fMRI techniques face challenges with speed, motion artifacts, and spatial resolution.
• Developing advanced imaging sequences is essential for improving fMRI data quality.

Purpose of the Study:

• To introduce and evaluate a novel 3D radial echo planar imaging (3D REPI) sequence.
• To demonstrate the sequence's capability for flexible, rapid, and motion-robust sampling in fMRI.
• To enhance the quality of brain imaging for fMRI applications.

Main Methods:

• The 3D REPI sequence builds upon the TURBINE approach, utilizing radial trajectories in 3D k-space.
• Iterative conjugate gradient, SENSE reconstruction, and time-segmented FFT were employed for acceleration and B0 inhomogeneity correction.
• Golden angle rotation facilitated sliding window reconstruction for brain BOLD fMRI.

Main Results:

• Successful whole-brain fMRI experiments were conducted at high resolutions (2 mm isotropic, 1x1x2 mm³).
• 3D REPI demonstrated improved sampling and image quality, particularly with twisted trajectories.
• The sequence proved effective in correcting for rigid motion during fMRI scans.

Conclusions:

• 3D REPI offers a flexible volumetric fMRI approach with motion correction and high spatial resolution.
• Sliding window reconstruction with 3D REPI yielded improved BOLD fMRI brain activation maps.
• This novel sequence enhances the potential of fMRI for neuroscientific research.