Progressive Multifocal Leukoencephalopathy in AIDS: Proton MR Spectroscopy Patterns of Asynchronous Lesions Confirmed by Serial Diffusion-Weighted Imaging and Apparent Diffusion Coefficient Mapping

Progressive multifocal leukoencephalopathy (PML) is a rare disease that occurs mainly in immunocompromised patients. Despite the progressive nature of the disease, the changes on MRI during the disease course - which may help in monitoring the disease process - have seldom been reported. Here we describe a patient with polymerase-chain-reaction-proven PML examined using serial diffusion-weighted imaging (DWI) and apparent-diffusion-coefficient mapping. Magnetic resonance spectroscopy (MRS) revealed that the demyelinating process was more active without significant neuronal loss at the newer and advancing edge of a lesion than in the older central part of the lesion. This case shows that MRI findings such as DWI and MRS may improve the diagnosis and the understanding of the pathophysiology of PML.