title: Hyperfixation of 99mTc-HMPAO and hypofixation of 123I-iomazenil in acute herpes encephalitis.
abstract: We studied two patients with herpes encephalitis (HSE) by [99mTc]HMPAO and [123I]iomazenil single photon emission computed tomography. Increased uptake of HMPAO was seen for up to 63 days in the HSE affected brain area. Iomazenil binds to benzodiazepine receptors and can measure neurone loss. Decreased iomazenil uptake was observed a few days after onset, at a time when hyperfixation of HMPAO occurred. Because in HSE neurone loss occurs simultaneously with hyperfixation of HMPAO, it is unlikely that this hyperfixation is caused by increased neuronal activity, as in epilepsy. This suggests that the hyperfixation of HMPAO in HSE occurs in glia and is sustained by inflammation-related hypermetabolism and acidity. The early neurone loss in HSE stresses the importance of immediate antiviral treatment.
authors.affiliation: Department of Neurology, University Central Hospital, Helsinki, Finland.
authors.forename: J
authors.initials: J
authors.lastname: Launes
authors.forename: L
authors.initials: L
authors.lastname: Hokkanen
authors.forename: P
authors.initials: P
authors.lastname: Nikkinen
authors.forename: K
authors.initials: K
authors.lastname: Liewendahl
authors.forename: O
authors.initials: O
authors.lastname: Salonen
authors.forename: J
authors.initials: J
authors.lastname: Sirén
authors.forename: M
authors.initials: M
authors.lastname: Iivanainen
mesh_terms: D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism; D004660:Encephalitis / Q000175:diagnosis* / Q000821:virology; D004668:Encephalitis Viruses; D005260:Female; D005442:Flumazenil / Q000031:analogs & derivatives*; D006561:Herpes Simplex / Q000175:diagnosis / Q000821:virology; D006801:Humans; D007457:Iodine Radioisotopes; D008875:Middle Aged; D015609:Organotechnetium Compounds; D010091:Oximes; D011963:Receptors, GABA-A / Q000378:metabolism; D019690:Technetium Tc 99m Exametazime; D013702:Temporal Lobe / Q000000981:diagnostic imaging; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
chemical_list: D007457:Iodine Radioisotopes; D015609:Organotechnetium Compounds; D010091:Oximes; D011963:Receptors, GABA-A; D019690:Technetium Tc 99m Exametazime; D005442:Flumazenil; C063038:iomazenil