Herpes simplex virus encephalitis: neuroradiological diagnosis

Herpes simplex virus encephalitis (HSE) is the most frequent viral encepahl itis,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 ra pidly. 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 unspe cific. We recommend the following examination protocol:coronar T1-weighted MR imag ing before and after adminstration of gadopentetate dimeglumine, coronar FL AIR sequence and axial T2-weighted imaging. The diagnostic proof is to show the evidence of viral DNA by polymerase chain reaction (PCR) in cerebrospi nal liquor.