Repeated functional magnetic resonance imaging of the lumbosacral cord during electrical stimulation of the tibial nerve

Motivation: Reliable clinical biomarkers for predicting recovery after spinal cord injury are lacking. Functional MRI of the lumbosacral cord could offer valuable insights into preserved function below the injury level. Goal(s): Our goal was to demonstrate the feasibility of lumbosacral cord fMRI during a sensory task and investigate the impact of scan length. Approach: We conducted fMRI in 20 healthy subjects during block-designed electrical stimulation of the right tibial nerve across two sessions. Results: Significant BOLD signal changes were observed in the ipsilateral dorsal region of the spinal cord. Although 24 minutes of acquisition proved sufficient, the second session detected considerably less activity. Impact: BOLD fMRI of the lumbosacral cord during transcutaneous electrical tibial nerve stimulation is feasible, and the required scan times of 24 minutes are clinically achievable. The differences between sessions suggest an impact of habituation, warranting further investigation.