BRIEF TITLE * (in English and Sufficiently Descriptive) Role of MRI in Anti-LGI1 Encephalitis

Study Overview
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Brief Summary
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The term autoimmune encephalitis denotes an heterogenous group of diseases commonly associated with autoantibodies targeting neural or glial antigens. Patients harboring antibodies against the leucine-rich glioma-inactivated protein 1 (LGI1) usually respond well to immunotherapy, but a significant percentage develop cognitive sequelae and disability nonetheless. These patients would likely benefit for more aggressive and prolonged immunotherapy, aiming to prevent permanent neurological deficits. Identifying features predicting poor outcome would be crucial to guide treatment decisions. Brain magnetic resonance imaging is a key diagnostic tool in the acute phase, but radiological changes may also appear in follow-up studies, including global brain atrophy, hippocampal atrophy and mesial temporal sclerosis. We hypothesize that specific changes identifiable in the acute and chronic phase underlie a higher risk of poor outcome and persistent neurological deficits.

Official Title
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Investigating the Prognostic Role of Brain MRI in Anti-LGI1 Encephalitis

Conditions
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Autoimmune Encephalitis

Intervention / Treatment
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* Other: Retrospective evaluation of specific brain MRI features


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: - Patients with a definite diagnosis of LGI1-antibody-associated encephalitis available MRI records Ascertained positivity for LGI1-antibodies in serum and/or CSF Exclusion Criteria: - Positivity for another antibody against neural or glial antigens MRI images not available Not enough clinical data to ascertain outcome

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| LGI1- Patients<br>Patients affected by autoimmune encephalitis with antibodies against LGI1 | Other: Retrospective evaluation of specific brain MRI features<br>* Initial brain MRI and subsequent follow-up studies will be reviewed to document the presence of specific MRI features, and their association with greater disease severity in the acute phase and/or neurological sequelae after encephalitis resolution will be investigated. More specifically, we will analyze the presence of: Brain MRI changes in the acute stage, i.e. < 3 months from symptoms onset, including abnormal signal intensity, altered diffusion and/or contrast enhancement in the hippocampus (unilateral/bilateral), abnormal signal intensity in basal ganglia, insula, and/or perisylvian cortex, presence of global brain atrophy, presence of hippocampal atrophy and/or MTS, hippocampal volumetry Brain MRI changes after acute phase resolution (> 6 months after symptoms onset) including abnormal signal intensity in the hippocampus (unilateral/bilateral), presence of global brain atrophy, presence of hippocampal atrophy and/or MTS, hippocampal volumetry<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cognitive dysfunction and disability | Main outcome measures will include cognitive dysfunction measured by appropriate neuropsychological evaluations, and psychiatric symptoms; it will be none, light, moderate, severe | 12 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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MRI, Autoimmune encephalitis, LGI1 antibodies