Cortical hypointensity in T2-weighted gradient-echo sequences in patients with progressive multifocal leukoencephalopathy

Introduction: Progressive multifocal leukoencephalopathy is a demyelinating disease of the central nervous system caused by the reactivation of the JC virus. This opportunistic encephalopathy mainly affects immunodepressed patients with stage III HIV infection, although in recent years it has also been found in association with treatment with immunosuppressors such as natalizumab. MRI plays an important role in both the early diagnosis and follow-up of this disease. Recently, it has been reported that hypointensities in U-fibers and cortex adjacent to white-matter lesions characteristic of the disease can be identified on T2-weighted gradient-echo and susceptibility-weighted sequences in patients with progressive multifocal leukoencephalopathy. Objective: We aimed to analyze the presence and usefulness of cortical hypointensity on T2-weighted gradient-echo sequences in relation to the diagnosis of progressive multifocal leukoencephalopathy and to review the literature on the topic. Material and methods: We analyze three cases of progressive multifocal leukoencephalopathy seen at our center in three patients with immunosuppression of different origins: one with stage III HIV infection, one with multiple sclerosis being treated with natalizumab, and one with rheumatoid arthritis being treated with rituximab. Results: In all three cases MRI showed the cortical hypointensity adjacent to the white-matter lesion in the T2-weighted gradient-echo sequence. In the patient with multiple sclerosis, this sign appeared earlier than the abnormal signal in the white matter. The patient being treated with rituximab was diagnosed postmortem and the pathology findings correlated with the MRI findings. Conclusion: The finding of cortical hypointensity on T2-weighted gradient-echo MRI sequences seems to support the diagnosis of progressive multifocal leukoencephalopathy, regardless of the type of immunosuppression, so this finding should routinely assessed in patients suspected of having this disease. (C) 2019 SERAM. Published by Elsevier Espana, S.L.U. All rights reserved.