Simultaneous zero echo time fMRI of rat brain and spinal cord.

PURPOSE

Functional assessments of the central nervous system (CNS) are essential for many areas of research. fMRI typically targets either the brain or the spinal cord, but usually not both, because of the obstacles associated with simultaneous image acquisitions from distant fields of view (FOVs) with conventional MRI. In this work, we establish a novel MRI approach that enables artifact-free, quiet, simultaneous fMRI of both brain and spinal cord, avoiding the need for dynamic shimming procedures.

METHODS

We used zero TE Multi-Band-SWeep Imaging with Fourier Transformation (MB-SWIFT) technique at 9.4 T in a simultaneous dual-FOV configuration and two separate RF transmit-receive surface coils. The first coil covered the rat brain, while the second was positioned approximately at the T13-L1 level of the rat's spinal cord with copper shielding to minimize the coupling between the RF coils. Eight Sprague-Dawley rats were used for hindlimb stimulation fMRI studies.

RESULTS

Robust and specific activations were detected in both the brain and spinal cord during hindlimb stimulation at individual and group levels. The results established the feasibility of the novel approach for simultaneous functional assessment of the lumbar spinal cord and brain in rats.

CONCLUSION

This study demonstrated the feasibility of a novel dual-FOV fMRI approach based on zero-TE MB-SWIFT and set the stage for translation to humans. The methodology enables comprehensive functional CNS evaluations of great value in different conditions such as pain, spinal cord injury, neurodegenerative diseases, and aging.