Histopathologic Correlate of a Specific Mri Feature in White Matter Disorders

Background and purpose: Radially oriented hypointense stripes in hyperintense cerebral white matter are recognized on T2-weighted images of certain lysosomal storage disorders. We compared in vivo and postmortem MR imaging findings with histopathologic findings in three patients with metachromatic leukodystrophy (MLD), globoid cell leukodystrophy (GLD) and infantile GM1 gangliosidosis (GM1) to understand this characteristic MR imaging pattern. Methods: The in vivo MR imaging protocol comprised T1-and T2-weighted spin echo, and FLAIR images. A postmortem MR imaging study of coronal 1-cm thick brain slices was performed after at least 5 weeks of Formalin fixation, and included T2-weighted spin echo images, and three-dimensional (3D)-FLAIR images with high spatial resolution. Afterwards the slices were embedded in paraffin, whole-mount sections were made and neuropathologic stains were applied. Results: Similar imaging features were found in the three examined patients on in vivo and postmortem imaging, with more prominent stripes in GLD and MLD than in GM1. Neuropathologic examination revealed that the stripes were related to relative sparing of myelin in the perivenular regions in GM1 and MLD, but lipid-containing glial cells were also present in these areas in MLD. Perivenular clusters of globoid cells containing lipid material in absence of any myelin corresponded to the stripes in GLD. Conclusion: Results of our postmortem study shows that radial stripes of white matter on MR images represented relative myelin sparing in some lysosomal storage disorders, but they may also represent lipid storage.