Simultaneous zero echo time fMRI of rat brain and spinal cord

Area of Science:

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

Background:

• Functional magnetic resonance imaging (fMRI) is crucial for CNS research, but simultaneous brain and spinal cord imaging is challenging with conventional MRI.
• Current MRI techniques often target either the brain or spinal cord separately, limiting comprehensive functional assessments.
• Obstacles include difficulties in acquiring simultaneous images from distant fields of view (FOVs) and the need for dynamic shimming.

Purpose of the Study:

• To develop and validate a novel MRI approach for artefact-free, quiet, simultaneous functional MRI (fMRI) of both the brain and spinal cord.
• To overcome the limitations of conventional MRI in acquiring simultaneous images from distant FOVs.
• To establish a method that avoids the need for dynamic shimming procedures.

Main Methods:

• Utilized a zero echo time (TE) Multi-Band-SWeep Imaging with Fourier Transformation (MB-SWIFT) technique at 9.4T.
• Employed a simultaneous dual-field of view (FOV) configuration with two separate radio frequency (RF) transmit-receive surface coils (one for the brain, one for the spinal cord).
• Applied copper shielding between RF coils to minimize signal interference and conducted hindlimb stimulation fMRI studies in eight Sprague-Dawley rats.

Main Results:

• Successfully detected robust and specific functional brain and spinal cord activations during hind paw stimulation.
• Demonstrated significant activations at both individual and group levels.
• Established the feasibility of the novel approach for simultaneous functional assessment of the lumbar spinal cord and brain in rats.

Conclusions:

• The novel dual-FOV fMRI approach based on zero-TE MB-SWIFT is feasible for simultaneous brain and spinal cord imaging.
• This methodology enables comprehensive functional CNS evaluations, valuable for studying conditions like pain, spinal cord injury, neurodegenerative diseases, and aging.
• The study sets the stage for potential translation of this technique to human applications.