Histopathologic correlates of radial stripes on MR images in lysosomal storage 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 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 fluid-attenuated inversion recovery imaging. Postmortem MR imaging, including coronal 1-cm-thick brain sections, was performed after at least 5 weeks of formalin fixation and included T2-weighted spin-echo images and 3D fluid-attenuated inversion recovery images with high spatial resolution. Afterward, the sections were embedded in paraffin, whole-mount sections were made, and neuropathologic stains were applied. RESULTS Similar imaging features were found in the three patients on in vivo and postmortem images, 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 showed 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.