Early and chronic gray matter volume changes in limbic encephalitis revealed by voxel-based morphometry

Area of Science:

• Neurology
• Neuroimaging
• Immunology

Background:

• Antibody-associated limbic encephalitis (LE) is a growing cause of epilepsy.
• Magnetic resonance imaging (MRI) typically shows mesiotemporal changes.
• Imaging findings in LE can vary with the associated antibody.

Purpose of the Study:

• To investigate early and chronic gray matter (GM) volume changes in antibody-associated LE.
• To utilize voxel-based morphometry (VBM) for detailed analysis.
• To differentiate imaging patterns based on LE subtypes.

Main Methods:

• VBM analysis of 73 MRI scans from 55 patients with antibody-associated LE.
• Patients categorized into early (≤2 years) and chronic (>2 years) groups.
• Subgroup analysis for glutamic acid decarboxylase (GAD)-associated LE and voltage-gated potassium channel (VGKC)-complex-associated LE.

Main Results:

• Early LE showed bilateral amygdalar GM volume increase.
• Chronic LE revealed resolved amygdala changes and right cerebellar GM volume reduction.
• VGKC-complex LE exhibited early amygdalar increase and chronic frontal GM increase.
• GAD-associated LE showed no early changes but chronic frontoparietal GM reduction.

Conclusions:

• LE predominantly affects the amygdala early, with resolution over time.
• Distinct MRI characteristics exist for different antibody-associated LE subtypes.
• These findings enhance the pathophysiological understanding of LE.