Index by author

Focal signal abnormalities at the depth of the cerebellar fissures in children have been reported and hypothesized to represent a novel pattern of bottom-of-fissure dysplasia. The authors report a series of 23 patients with a similar distribution and appearance of cerebellar signal abnormality attributable to watershed injury. T2 prolongation was observed at the depths of the cerebellar fissures bilaterally in all 23 patients, centered at the expected location of the deep cerebellar vascular borderzone. Diffusion restriction was associated with MR imaging performed during acute injury in 13/16 patients. Five of 23 patients had prior imaging, all demonstrating a normal cerebellum. The etiology of injury was hypoxic-ischemic injury in 17/23 patients, posterior reversible encephalopathy syndrome in 3/23 patients, and indeterminate in 3/23 patients.

In this review, the authors provide an appraisal of the current literature on the physics principles, histopathologic validation, and clinical applications of advanced diffusion techniques in both brains and spinal cords of patients with MS (neurite orientation dispersion and density imaging, diffusion basis spectrum imaging, multicompartment microscopic diffusion MR imaging with the spherical mean technique, and models enabled through high-gradient diffusion MR imaging). They discuss limitations of each of the methods and directions that future research could take to provide additional validation of their roles as biomarkers of axonal and myelin injury in MS.