Spinal cord fMRI with MB-SWIFT for assessing epidural spinal cord stimulation in rats

Magn Reson Med, 2021 · DOI: 10.1002/mrm.28844 · Published: October 1, 2021

Simple Explanation

Electrical epidural spinal cord stimulation (SCS) is used to treat chronic pain and restore motor function after spinal cord injury. Monitoring spinal cord activity during SCS with fMRI could provide objective measures of treatment responses. This study introduces multi-band sweep imaging with Fourier transformation (MB-SWIFT) technique for spinal cord fMRI during SCS in rats.

Study Duration

Not specified

Participants

Six adult male Sprague-Dawley rats

Evidence Level

Not specified

Key Findings

1
MB-SWIFT was tolerant to electrode-induced artifacts and respiratory motion, leading to substantially higher fMRI sensitivity than spin echo fMRI.
2
Clear stimulation frequency-dependent responses to SCS were detected in the rat spinal cord close to the stimulation site.
3
The origin of MB-SWIFT fMRI signals was consistent with dominant inflow effects.

Research Summary

This study demonstrates the feasibility of spinal cord fMRI during SCS in rats using MB-SWIFT to overcome obstacles associated with spinal cord imaging. High-quality fMRI of the rat spinal cord was performed at 9.4 Tesla during simultaneous SCS, monitoring responses to electrical stimulation despite implanted electrodes. MB-SWIFT fMRI allows robust detection of fMRI responses in the spinal cord, even in the presence of electrodes, opening new avenues for SCS investigations.

Practical Implications

Spinal Cord Injury

MB-SWIFT fMRI can be used to investigate spinal cord injury and recovery processes.

Pain Management

This technique provides a framework for assessing the effects of SCS on pain pathways in the central nervous system.

Plasticity Assessment

MB-SWIFT can be used to study the plasticity of the spinal cord in response to stimulation and injury.

Study Limitations

1
MB-SWIFT's functional contrast depends on coil geometry because it relies on blood movement and inflow.
2
The entire volume seen by the receiver coil must be encoded and included in the FOV.
3
Signal from materials with short T2s can be received due to MB-SWIFT's near-zero acquisition delay.

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