Multimodal MRI evaluation of acute mild-contusive injury in mouse spinal cord

In vivo preclinical imaging of spinal cord injury (SCI) in rodent models is sought after for obtaining clinicallyrelevant neuropatholocial information in translational research. This paper uses multimodal magnetic resonance imaging (MRI) to investigate spinal cords that were injured mildly at the thoracic T11 level in six C57BL/6female mice. On postinjury days 1 and 3, the mice were subjected to neurobehavioral evaluations proceeded byhigh resolution MRI scans. The MRI protocols included proton density weighted, T2-weighted and diffusion tensor imaging. The scans on day 3, the injured cords were evaluated using postmortem histological analysis.The neurobehavioral tests indicated that injured mouse developed functional deficits in hindlimbs that worsen slowly from day 1 to day 3. Microanatomical images from these days depicted slight variations in the intensitypatterns within the injured SC parenchyma. These changes suggested gradually progressive neuropathology.The quantitative diffusion tensor measurements showed steady deterioration of the neurostructure, prominentlyin the dorsal region which received the mechanical impact. The injured cords examined with differentstains depicted gross tissue morphology that matched the anatomical images and allowed interpreting the neurostructural data. At the injury site, changes in the grey and white matters and neuronal cell swelling were evident and supported the diffusion measurements, but the fibrotic tissue deposition was minimal. The results together demonstrated the value of evaluating injured mouse SC using in vivo MRI and how this may potentiallyplay an important role in characterizing the efficacy of a therapeutic strategy aimed at improving the outcome from SCI.