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Spinal cord fMRI with MB‐SWIFT for assessing epidural spinal cord stimulation in rats
Author(s) -
Laakso Hanne,
Lehto Lauri J.,
Paasonen Jaakko,
Salo Raimo,
Canna Antonietta,
Lavrov Igor,
Michaeli Shalom,
Gröhn Olli,
Mangia Silvia
Publication year - 2021
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.28844
Subject(s) - spinal cord , neuroscience , cord , stimulation , functional magnetic resonance imaging , spinal cord injury , medicine , magnetic resonance imaging , psychology , radiology , surgery
Purpose Electrical epidural spinal cord stimulation (SCS) is used as a treatment for chronic pain as well as to partially restore motor function after a spinal cord injury. Monitoring the spinal cord activity during SCS with fMRI could provide important and objective measures of integrative responses to treatment. Unfortunately, spinal cord fMRI is severely challenged by motion and susceptibility artifacts induced by the implanted electrode and bones. This pilot study introduces multi‐band sweep imaging with Fourier transformation (MB‐SWIFT) technique for spinal cord fMRI during SCS in rats. Given the close to zero acquisition delay and high bandwidth in 3 dimensions, MB‐SWIFT is demonstrated to be highly tolerant to motion and susceptibility‐induced artifacts and thus holds promise for fMRI during SCS. Methods MB‐SWIFT with 0.78 × 0.78 × 1.50 mm 3 spatial resolution and 3‐s temporal resolution was used at 9.4 Tesla in rats undergoing epidural SCS at different frequencies. Its performance was compared with spin echo EPI. The origin of the functional contrast was also explored using suppression bands. Results MB‐SWIFT was tolerant to electrode‐induced artifacts and respiratory motion, leading to substantially higher fMRI sensitivity than spin echo fMRI. Clear stimulation frequency‐dependent responses to SCS were detected in the rat spinal cord close to the stimulation site. The origin of MB‐SWIFT fMRI signals was consistent with dominant inflow effects. Conclusion fMRI of the rat spinal cord during SCS can be consistently achieved with MB‐SWIFT, thus providing a valuable experimental framework for assessing the effects of SCS on the central nervous system.