Uncommon 18F-FDG-PET/CT findings in patients affected by limbic encephalitis: hyper-hypometabolic pattern with double antibody positivity and migrating foci of hypermetabolism

Clin Imaging. 2015 Mar-Apr;39(2):329-33. doi: 10.1016/j.clinimag.2014.09.004. Epub 2014 Oct 16.

Abstract

Autoimmune limbic encephalitis (LE) is a rare disorder; its diagnosis can be challenging. We report two uncommon cases of LE evaluated by brain 2-deoxy-2-[18F]fluoro-d-glucose ((18)F-FDG) positron emission tomography/computed tomography describing the metabolic imaging patterns, which were different from those observed in previous studies: the first one presented an unprecedented (18)F-FDG brain mixed pattern, involving also the midbrain, despite negative magnetic resonance imaging exams; the second one showed migrating foci of hypermetabolism, one of which turned into hypometabolism at a later examination.

Keywords: (18)F-FDG PET/CT; Autoimmune limbic encephalitis; GAD; MRI; NMDAR.

Publication types

  • Case Reports

MeSH terms

  • Antibodies / analysis
  • Autoimmune Diseases / diagnosis*
  • Autoimmune Diseases / immunology
  • Autoimmune Diseases / metabolism*
  • Brain / diagnostic imaging
  • Brain / metabolism*
  • Brain / pathology
  • Female
  • Fluorodeoxyglucose F18*
  • Humans
  • Limbic Encephalitis / diagnosis*
  • Limbic Encephalitis / immunology
  • Limbic Encephalitis / metabolism*
  • Magnetic Resonance Imaging*
  • Middle Aged
  • Positron-Emission Tomography*
  • Tomography, X-Ray Computed
  • Young Adult

Substances

  • Antibodies
  • Fluorodeoxyglucose F18

Supplementary concepts

  • Autoimmune limbic encephalitis