[Herpes simplex virus encephalitis: neuroradiologic differential diagnosis].

Herpes simplex virus encephalitis (HSE) is the most frequent viral encephalitis, as a rule with the starting point and centre within the temporal lobe. If untreated, HSE is usually fatal, thus diagnosis has to be established rapidly. Treatment with Acyclovir should begin as soon as possible. As MRI is extremely sensitive in detecting the early inflammatory changes, it should be initially performed, especially as in the early stadium CT may be unspecific. We recommend the following examination protocol: coronar T1-weighted MR imaging before and after administration of gadopentetate dimeglumine, coronar FLAIR sequence and axial T2-weighted imaging. The diagnostic proof is to show the evidence of viral DNA by polymerase chain reaction (PCR) in cerebrospinal liquor.