Test-Retest Reliability of Sensorimotor Activity Measured With Spinal Cord fMRI

Area of Science:

• Neuroimaging
• Spinal Cord Physiology
• Functional Magnetic Resonance Imaging

Background:

• Spinal cord functional magnetic resonance imaging (fMRI) is crucial for evaluating interventions.
• Previous research localized human motor activity to the ipsilateral ventral horn.
• The test-retest reliability of spinal fMRI is not well-established.

Purpose of the Study:

• To assess the test-retest reliability of spinal fMRI during a sensorimotor task.
• To investigate spinal cord activation patterns during right-hand grasping and grip force estimation.
• To determine factors influencing the reliability of spinal fMRI measurements.

Main Methods:

• 30 healthy volunteers underwent two identical fMRI scanning visits.
• Participants performed a right-hand grasping and grip force estimation task.
• Test-retest reliability was assessed within and between scanning visits.

Main Results:

• Motor-evoked activation was observed in ipsilateral ventro-dorsal (C5-T1) and medial (C2-C3) spinal cord regions.
• Despite reliable task performance and signal quality, motor activation reliability was poor-to-fair.
• Increased task runs improved group-level activation robustness but not individual reliability.

Conclusions:

• Spinal fMRI activation corresponds to known motor circuit organization.
• Low test-retest reliability of spinal fMRI poses a challenge for clinical applications.
• Understanding inherent within-individual variability is crucial for improving spinal fMRI reliability.