Semi-quantitative analysis of cerebral FDG-PET reveals striatal hypermetabolism and normal cortical metabolism in a case of VGKCC limbic encephalitis.

Abstract

In the context of delayed autoimmune encephalitis antibody results, functional imaging can support the diagnosis of limbic encephalitis associated with anti-voltage-gated potassium channel complex (VGKCC) antibodies. Here we present a typical case of VGKCC encephalitis in a 69-year-old woman whose symptoms responded to plasmapheresis. A cerebral 18F-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET) scan performed prior to commencing treatment revealed striatal hypermetabolism assessed qualitatively and semi-quantitatively, with normal uptake in the cortex and cerebellum when analysed semi-quantitatively. Repeat FDG-PET imaging performed three months later revealed normalisation of striatal hypermetabolism. Previous case reports have described striatal hypermetabolism and/or cortical hypometabolism in patients with VGKCC encephalitis. However, most of these descriptions were based on qualitative analyses only and may represent the relative change in cortical metabolism compared with striatal metabolism. We recommend semi-quantitative analysis of cerebral FDG-PET, in addition to reporting the qualitative FDG-PET images.

• Authors: Patrick Moloney, Ruth Boylan, Marwa Elamin, Sean O'Riordan, Ronan Killeen, Christopher McGuigan
• Journal: The neuroradiology journal (Neuroradiol J) Vol. 30 Issue 2 Pg. 160-163 (Apr 2017) ISSN: 2385-1996 [Electronic] United States
• PMID: 28424014 (Publication Type: Case Reports, Journal Article)

Chemical References

• Antibodies
• Potassium Channels, Voltage-Gated
• Fluorodeoxyglucose F18

Topics

• Aged
• Antibodies (blood)
• Cerebral Cortex (diagnostic imaging)
• Corpus Striatum (diagnostic imaging)
• Female
• Fluorodeoxyglucose F18
• Humans
• Limbic Encephalitis (diagnostic imaging, immunology, pathology)
• Positron-Emission Tomography
• Potassium Channels, Voltage-Gated (immunology)