- Cerebellar Watershed Injury in Children
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.
- Sensitivity of the Inhomogeneous Magnetization Transfer Imaging Technique to Spinal Cord Damage in Multiple Sclerosis
Anatomic images covering the cervical spinal cord from the C1 to C6 levels and DTI, magnetization transfer/inhomogeneous magnetization transfer images at the C2/C5 levels were acquired in 19 patients with MS and 19 paired healthy controls. Anatomic images were segmented in spinal cord GM and WM, both manually and using the AMU40 atlases. MS lesions were manually delineated. MR imaging metrics were analyzed within normal-appearing and lesion regions in anterolateral and posterolateral WM and compared using Wilcoxon rank tests and z scores. The use of a multiparametric MR imaging protocol combined with an automatic template-based GM/WM segmentation approach in the current study outlined a higher sensitivity of the ihMT technique toward spinal cord pathophysiologic changes in MS compared with atrophy measurements, DTI, and conventional MT. The authors also conclude that the clinical correlations between ihMTR and functional impairment observed in patients with MS also argue for its potential clinical relevance, paving the way for future longitudinal multicentric clinical trials in MS.
- Hippocampal Sclerosis Detection with NeuroQuant Compared with Neuroradiologists
The authors reviewed 144 adult patients who underwent presurgical evaluation for temporal lobe epilepsy. The reference standard for hippocampal sclerosis was defined by having hippocampal sclerosis on pathology (n=61) or not having hippocampal sclerosis on pathology (n=83). Sensitivities, specificities, positive predictive values, and negative predictive values were compared between NeuroQuant analysis and visual MR imaging analysis. Visual MR imaging analysis by a neuroradiologist with expertise in epilepsy had a higher sensitivity than did NeuroQuant analysis, likely due to the inability of NeuroQuant to evaluate changes in hippocampal T2 signal or architecture. Given that there was no significant difference in specificity between NeuroQuant analysis and visual MR imaging analysis, NeuroQuant can be a valuable tool when the results are positive, particularly in centers that lack neuroradiologists with expertise in epilepsy, to help identify and refer candidates for temporal lobe epilepsy resection.