title: Fluorodeoxyglucose positron emission tomography in anti-N-methyl-D-aspartate receptor encephalitis: distinct pattern of disease.
abstract: BACKGROUND
  Patients with encephalitis associated with antibodies against N-methyl-D-aspartate-receptor antibody (NMDAR-ab) encephalitis frequently show psychotic symptoms, amnesia, seizures and movement disorders. While brain MRI in NMDAR-ab encephalitis is often normal, abnormalities of cerebral glucose metabolism have been demonstrated by positron emission tomography (PET) with 18F-fluorodeoxyglucose(FDG) in a few usually isolated case reports. However, a common pattern of FDG-PET abnormalities has not been reported.
  
  
  METHODS
  The authors retrospectively identified six patients with NMDAR-ab encephalitis in two large German centres who underwent at least one whole-body FDG-PET for tumour screening between January 2007 and July 2010. They analysed the pattern of cerebral uptake derived from whole-body PET data for characteristic changes of glucose metabolism compared with controls, and the changes of this pattern during the course of the disease.
  
  
  RESULTS
  Groupwise analysis revealed that patients with NMDAR-ab encephalitis showed relative frontal and temporal glucose hypermetabolism associated with occipital hypometabolism. Cross-sectional analysis of the group demonstrated that the extent of these changes is positively associated with clinical disease severity. Longitudinal analysis of two cases showed normalisation of the pattern of cerebral glucose metabolism with recovery.
  
  
  CONCLUSIONS
  A characteristic change in cerebral glucose metabolism during NMDAR-ab encephalitis is an increased frontotemporal-to-occipital gradient. This pattern correlates with disease severity. Similar changes have been observed in psychosis induced by NMDAR antagonists. Thus, this pattern might be a consequence of impaired NMDAR function.
authors.affiliation: Department of Neurology, University Medical Center Eppendorf, Martinistr 52, Hamburg, Germany. f.leypoldt@uke.uni-hamburg.de
authors.forename: Frank
authors.initials: F
authors.lastname: Leypoldt
authors.forename: Ralph
authors.initials: R
authors.lastname: Buchert
authors.forename: Ingo
authors.initials: I
authors.lastname: Kleiter
authors.forename: Jörg
authors.initials: J
authors.lastname: Marienhagen
authors.forename: Mathias
authors.initials: M
authors.lastname: Gelderblom
authors.forename: Tim
authors.initials: T
authors.lastname: Magnus
authors.forename: Josep
authors.initials: J
authors.lastname: Dalmau
authors.forename: Christian
authors.initials: C
authors.lastname: Gerloff
authors.forename: Jan
authors.initials: J
authors.lastname: Lewerenz
mesh_terms: D000328:Adult; D060426:Anti-N-Methyl-D-Aspartate Receptor Encephalitis / Q000473:pathology*; D001921:Brain / Q000378:metabolism / Q000473:pathology*; D005260:Female; D019788:Fluorodeoxyglucose F18; D005625:Frontal Lobe / Q000473:pathology; D005947:Glucose / Q000378:metabolism; D006801:Humans; D008297:Male; D059906:Neuroimaging / Q000379:methods; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D013702:Temporal Lobe / Q000378:metabolism / Q000473:pathology; D055815:Young Adult
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D005947:Glucose