[Progressive multifocal leukoencephalopathy. Role of imaging in its diagnosis. Perspectives].

We review five cases of Progressive Multifocal Leukoencephalopathy (PML), confirmed by biopsy in three cases and by LCR JC virus research by PCR (polymerase chain reaction) in two cases. We analysed the lesions and different forms of imagiological presentation, concerning location, mass effect, contrast enhancement and progress, and emphasize the importance of some atypical patterns. Reference is also made to the role of imaging in its diagnosis and new techniques, such as Spectroscopy and Transfer Magnetization, to avoid brain biopsy.