Limbic encephalitis, specifically depicted by PET

A 44-year-old woman suffered from limbic encephalitis, possibly caused by herpes simplex virus. Neither CT-scanning nor MR-imaging showed a persistent lesion. Positron emission tomography, however, indicated a metabolic deficit in circumscript limbic structures, namely gyrus cinguli and temporal cortices. This distribution supported the clinical diagnosis. Moreover, it suggested a close relation of the gyrus cinguli with the organization of limbic functions in the brain. It might support suggestions made in the literature that the gyrus cinguli is more frequently affected by HSV encephalitis. Further PET-studies in cases of limbic encephalitis would be of interest.