Subcortical Hypermetabolism Associated With Cortical Hypometabolism Is a Common Metabolic Pattern in Patients With Anti-Leucine-Rich Glioma-Inactivated 1 Antibody Encephalitis

Abstract

PurposeBrain 18F-fluorodeoxyglucose positron emission tomography (FDG PET) is a sensitive technique for assisting in the diagnosis of patients with anti-leucine-rich glioma-inactivated 1 (LGI1) antibody encephalitis. However, the common pattern of this disorder assessed by FDG PET remains unknown. The present study aimed to explore the glucose metabolic patterns of this disorder based on PET voxel analysis.MethodsThis retrospective study enrolled 25 patients with anti-LGI1 encephalitis, who were admitted in Beijing Tiantan Hospital between September 2014 and July 2019. The glucose metabolic pattern was compared between the included patients and 44 age- and gender-matched healthy controls using Statistical Parametric Mapping. Then, the correlation between the metabolic pattern and scaled activities of daily living (ADLs) of the patients was assessed.ResultsThe median time from symptom onset to PET scans was 9 w (range:2-53w). The groupwise analysis revealed that patients with anti-LGI1 encephalitis had left hippocampal hypermetabolism and hypometabolism in almost all neocortical regions. The individual-level results showed most patients presented a decreased metabolism in neocortical regions, as well as an increase in metabolism in the hippocampus and basal ganglia. Furthermore, the metabolic gradient between hippocampus and neocortical regions was positively associated with the ADLs (frontal lobe, r=0.529, P=0.008; parietal lobe, r=0.474, P=0.019; occipital lobe, r=0.413, P=0.045; temporal lobe, r=0.490, P=0.015), respectively. In addition, the patients with facio-brachial dystonic seizures (FBDS) presented bilateral putamen hypermetabolism, when compared to patients without FBDS and healthy controls.ConclusionSubcortical hypermetabolism associated with cortical hypometabolism presented with a common metabolic pattern in patients with anti-LGI1 encephalitis in the present study. The resolution of the metabolic gradient of the hippocampal hypermetabolism and neocortical hypometabolism may bring about improved clinical neurologic disability.

Dopamine, Immunity, and Disease

“…Changes in dopamine and metabolite levels due to hyper- and hypometabolism at different disease stages could explain the increases and decreases in dopamine and metabolite levels seen over time during HIV infection and/or exposure to viral proteins. Further, glucose hypermetabolism was identified by PET scans with 18F-FDG in the basal ganglia, and this correlated with several forms of encephalitis and is often coupled to hypometabolism in other brain regions ( Rey et al, 2012 ; Wegner et al, 2014 ; Zhao et al, 2021 ). In rodents, a dual tracer PET analysis of glucose (18F-FDG, 18F-GE) and microglial activation (TSPO) correlated hypermetabolism with microglial activity and neuroinflammation ( Brendel et al, 2017 ).…”

Cortical metabolic characteristics of anti-leucine-rich glioma-inactivated 1 antibody encephalitis based on 18F-FDG PET

“…Serum and cerebrospinal fluid samples were collected from all patients for antibody detection, including LGI1, N-methyl D-aspartate receptor, contactin-associated protein 2, α-amino-3-hydroxy-5methyl-4-isoxazolepropionic acid receptor, and γ-aminobutyric acid type B. Both sample types were tested for the presence of LGI1 antibodies as described in our previous study (15). The presence of antibody in serum and cerebrospinal fluid samples was determined based on the judgment of two experienced investigators.…”

“…Previous studies on anti-LGI1 encephalitis using 18 F-FDG PET have mainly focused on the metabolic alterations occurring within entire cerebral lobes (temporal, parietal, or frontal lobe), deep nuclei, or the hippocampus (12)(13)(14)(15). The present study aimed to assess the laterality of changes in cortical metabolism and the patterns within specific sub-lobar regions among patients with anti-LGI1 encephalitis via analysis using Cortex ID software to promote our understanding of the varied clinical manifestations associated with regional metabolic abnormalities.…”

Approach to acute encephalitis in the intensive care unit

“…In a prospective cohort of 20 patients with suspected limbic encephalitis, combining 18 F-FDG/PET and MRI has shown significantly higher diagnostic yield when compared with MRI as the sole imaging modality [27]. Characterizing specific patterns of metabolic derangement could help to distinguish between different types of AE earlier in the disease course [28]. Patients with anti-NMDAR had substantially reduced medial occipital lobe metabolism relative to other types of AE [29].…”