MR Imaging Findings in Anti-Leucine-Rich Glioma Inactivated Protein 1 Encephalitis: A Systematic Review and...

Area of Science:

• Neuroimmunology
• Neuroradiology
• Molecular Neuroscience

Background:

• Antibodies against leucine-rich glioma inactivated protein 1 (LGI1) are a frequent cause of autoimmune encephalitis.
• MR imaging may reveal T2 FLAIR hyperintensities in the medial temporal lobe (MTL), basal ganglia involvement, or be unremarkable in these cases.

Approach:

• A systematic review and meta-analysis were conducted to determine the prevalence of MR imaging abnormalities in anti-LGI1 encephalitis.
• Literature searches were performed on PubMed and Web of Science up to April 7, 2022.
• Thirty-one studies with over 10 patients each and available MR imaging data were included.

Key Points:

• T2 FLAIR-MTL hyperintensities were observed in 54% of 1318 patients across 30 studies.
• Bilateral and unilateral T2 FLAIR-MTL abnormalities were present in 27% and 24% of patients, respectively.
• Basal ganglia abnormalities were noted in 10% of 612 patients across 15 studies.

Conclusions:

• T2 FLAIR-MTL hyperintensities are present in approximately half of anti-LGI1 encephalitis cases.
• The similar prevalence of unilateral and bilateral findings suggests unilaterality can be indicative of LGI1 encephalitis in the right clinical setting.
• Basal ganglia abnormalities in about 10% of cases warrant focused attention, and LGI1 expression patterns correlate with observed MR imaging findings.