Perfusion imaging metrics after acute traumatic spinal cord injury are associated with injury severity in rats and humans

Traumatic spinal cord injury (tSCI) causes an immediate loss of neurological function, and the prediction of recovery is difficult in the acute phase. In this study, we used contrast-enhanced ultrasound imaging to quantify intraspinal vascular disruption acutely after tSCI. In a rodent thoracic tSCI model, contrast-enhanced ultrasound revealed a perfusion area deficit that was positively correlated with injury severity and negatively correlated with hindlimb locomotor function at 8 weeks after injury. The spinal perfusion index was calculated by normalizing the contrast inflow at the injury center to the contrast inflow in the injury periphery. The spinal perfusion index decreased with increasing injury severity and positively correlated with hindlimb locomotor function at 8 weeks after injury. The feasibility of intraoperative contrast-enhanced ultrasound imaging was further tested in a cohort of 27 patients with acute tSCI of varying severity and including both motor-complete and motor-incomplete tSCIs. Both the perfusion area deficit and spinal perfusion index were different between motor-complete and motor-incomplete patients. Moreover, the perfusion area deficit and spinal perfusion index correlated with the injury severity at intake and exhibited a correlation with extent of functional recovery at 6 months. Our data suggest that intraoperative contrast-enhanced, ultrasound-derived metrics are correlated with injury severity and chronic functional outcome after tSCI. Larger clinical studies are required to better assess the reliability of the proposed contrast-enhanced ultrasound biomarkers and their prognostic capacity.