Functional magnetic resonance imaging using non-Fourier, spatially selective radiofrequency encoding

Area of Science:

• Magnetic Resonance Imaging
• Neuroimaging
• Biophysics

Background:

• Standard multislice functional MRI (fMRI) methods face limitations in monitoring irregularly distributed brain sections and can be affected by in-flow effects.
• Optimizing signal-to-noise ratio and minimizing artifacts are crucial for accurate fMRI-based functional mapping.

Purpose of the Study:

• To introduce and evaluate a new non-Fourier encoding method for fMRI using spatially selective radiofrequency (RF) excitation.
• To demonstrate the advantages of this method, including reduced in-flow effects and flexible volume monitoring.

Main Methods:

• Developed a non-Fourier encoding technique manipulating spatially selective RF pulses to encode spins in the slice-select direction.
• Adapted an interleaved echo-planar imaging (EPI) sequence for non-Fourier encoding and implemented it on a 1.5-Tesla MRI system.
• Applied the method for functional mapping of visual and motor areas.

Main Results:

• The non-Fourier encoding method successfully reduced in-flow effects during fMRI.
• Demonstrated the capability to monitor irregularly distributed sections without encoding the entire volume.
• Showcased potential for increased signal-to-noise ratio with appropriate encoding basis selection.

Conclusions:

• The presented non-Fourier encoding method offers significant advantages for fMRI, including reduced artifacts and flexible data acquisition.
• This technique can be adapted to various fMRI sequences, such as single-shot EPI, for enhanced neuroimaging.
• The method provides a promising approach for improved functional mapping of brain activity.