Dynamic per slice shimming for simultaneous brain and spinal cord fMRI

Area of Science:

• Neuroimaging
• Magnetic Resonance Imaging (MRI)
• Central Nervous System (CNS) research

Background:

• Simultaneous functional MRI (fMRI) of the brain and spinal cord is a developing technique for CNS studies.
• Challenges include poor B0 homogeneity and the small size of the spinal cord.
• Existing dynamic shimming approaches are extended for improved simultaneous imaging.

Purpose of the Study:

• To enhance simultaneous brain and spinal cord fMRI by extending dynamic shimming.
• To overcome obstacles like poor B0 homogeneity and small spinal cord size.
• To achieve high-resolution imaging of both brain and spinal cord.

Main Methods:

• Dynamic shimming optimized linearly for gradients and frequency offset per slice.
• Minimized off-resonance effects for both brain and spinal cord.
• Simultaneous fMRI acquisition using echo-planar RF pulse with reduced FOV for spinal cord and full FOV for brain.

Main Results:

• Acquired high-clarity T2*-weighted images of brain and spinal cord with minimal artifacts.
• Demonstrated task-consistent activation in motor cortices, cerebellum, and C6-T1 spinal segments during a fist-clenching task.
• Obtained high-quality functional results at the individual level for both brain and spinal cord.

Conclusions:

• The developed method yields high-quality functional MRI results for sensory-motor tasks.
• Consistent activation is observed in both brain and spinal cord at individual levels.
• The reduced FOV excitation technique is versatile for any spinal cord section, indicating significant future potential.