Wallerian degeneration after spinal cord lesions in cats detected with diffusion tensor imaging

Diffusion Tensor Imaging as a Predictor of Locomotor Function after Experimental Spinal Cord Injury and Recovery

“…2,3 While efforts to understand and overcome these barriers are active areas of research, clinical assessments of locomotor function using motor/sensory testing and spinal white matter integrity via imaging remain critical aspects of comprehensive post-SCI analyses and are used to track (potential) recovery after trauma. [3][4][5][6][7][8][9][10][11][12][13][14][15] Current imaging modalities such as conventional magnetic resonance (MR) illustrate SCI pathology at the level of the whole cord; however, evaluation of individual cord components such as white matter tracts remains more complex. Diffusion tensor imaging (DTI), an MR imaging technique, allows for the examination of white matter directionality and relative health by measuring the anisotropic diffusion of water in the white matter.…”

“…To date, preclinical studies of traumatic SCI evaluation using DTI have used transection, 5,[21][22][23][24][25][26] compression, 27 ischemic, 28 and contusion injury models 4,7,11,[29][30][31][32][33][34] with many focusing on locomotor and histological correlations. From a translational standpoint, a preclinical SCI model in which non-invasive techniques can recognize graded injury severity and prognosticate recovery has significant implications for assessing therapeutic interventions and complementing clinical evaluations.…”

Time-Dependent Structural Changes of the Dentatothalamic Pathway in Children Treated for Posterior Fossa Tumor

“…Prior studies have reported the sensitivity of diffusion MR imaging to axonal injury and have shown diffusion changes distal to the site of the lesion, [23][24][25] suggesting detection of Wallerian degeneration, which occurs when axons are separated from their cell body. 26 The DTT tract is the main outflow of the cerebellum, and it has been suggested that injury to the cerebellum and degeneration of this cerebrocerebellar pathway may be involved in cognitive dysfunction and PFS.…”

“…23,41 In those studies, further assessment revealed decreased ʈ in the acute period (1 week) and elevated -at a later time (21 days to 2 months) after injury. 23,40,41 Given that ʈ may be more sensitive to axonal degeneration, whereas -changes may be driven by myelin effects, these studies suggested that varying contributions from axonal degeneration and myelin breakdown along different time points likely impacted temporal tensor differences, including both FA and MD. 23,40,41 Other studies have also suggested that an increase in -may drive the reduction in FA that occurs at a later time point in axonal degeneration.…”

“…23,40,41 Given that ʈ may be more sensitive to axonal degeneration, whereas -changes may be driven by myelin effects, these studies suggested that varying contributions from axonal degeneration and myelin breakdown along different time points likely impacted temporal tensor differences, including both FA and MD. 23,40,41 Other studies have also suggested that an increase in -may drive the reduction in FA that occurs at a later time point in axonal degeneration. [42][43][44] While individual FA and MD are not sufficient to differentiate axonal-versus-myelin degeneration, a pronounced reduction in FA and an increase in MD in the subacute period likely reflect the combined effects of active or ongoing myelin breakdown and inflammation after initial cerebellar injury.…”