Metabolic Imaging for Diagnosis and Prognostication of Autoimmune encephalitiS (MIDAS)

Autoimmune encephalitis (AE) is a rare neurological disorder mediated by autoimmune antibody response against neuronal cell surface and intraneuronal proteins associated with specific brain areas, resulting in severe inflammation and damage in the associated brain regions, all most frequently manifesting diverse cognition and memory impairment symptoms at follow-up. However, these symptoms may co-exist or mimic other CNS autoimmune and neurodegenerative disorders. The most common guideline for diagnosing autoimmune encephalitis relies on cerebrospinal fluid (CSF) antibody testing which might take several weeks to obtain, making it not optimal for the early diagnosis of AE. As for magnetic resonance imaging (MRI), which is the most common imaging tool utilized for aiding in the diagnosis of AE, can possess several limitations as some patients, like anti-NMDAr AE patients, can present memory and behavioral deficits even in the presence of normal brain MRI. Positron emission tomography (PET) with 2-deoxy-2-[fluorine-18] fluoro-D-glucose (18F-FDG) have been addressed by several studies as an important examination for the early diagnosis of AE . One study demonstrated that the fraction of having an abnormal MRI in AE patients is lower than having an abnormal PET, by which certain PET patterns were associated with autoantibody types of AE. Moreover, one report demonstrated that even with autoantibody negative test and normal brain MRI, FDG-PET examination showed abnormal hypometabolism and hypermetabolism patterns. More specifically, these distinct patterns include medial temporal and striatal hypermetabolism with cortical diffuse hypometabolism. Leiris et al. revealed that the methadology used for the analysis of these PET images is highly variable, especially intensity normalization methods, where most possess some limitations (e.g., proportional scaling) as they can impede the accurate differential diagnosis of autoimmune encephalitis (AE) by potentially indicating false hypermetabolism in otherwise preserved brain regions. Absolute quantification is not possible since the disease presents both diffuse hypometabolism and hypermetabolism on PET images. So, they suggested that it's best to parametrize the brain's activity by dividing it by that of the striatum. Their voxel-based analysis, comparing individuals with AE to both healthy subjects and those with mild cognitive impairment (MCI), demonstrated that a decrease in the cortex/striatal metabolic ratio is a robust biomarker for the early diagnosis of AE.

Study Overview

• Status: Active, not recruiting
• Conditions: Autoimmune Encephalitis; Paraneoplastic Neurological Syndrome
• Intervention / Treatment: Other: PET-Scan analysis

• Study Type: Observational
• Enrollment (Actual): 28

Contacts and Locations

Study Locations

• France
  • Pierre-Bénite, France, 69495
    • CHU Lyon

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Patients will be included from the from the database of the French Reference Centre for Paraneoplastic Neurological Syndromes and Autoimmune Encephalitis (Lyon, France)

Description

Inclusion Criteria:

• patient with positivity of auto-antibody in CSF
• patient >18 years old
• patient with auto-immune encephalitis or paraneoplastic neurological syndrome

Exclusion Criteria:

- patient without data

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Auto-immune encephalitis patients; Analysis of PET-scan	Other: PET-Scan analysis; Investigate and determine the clinical value of different cortex/striatal metabolic ratio patterns in each antibody-specific subtype of autoimmune encephalitis
Paraneoplastic Neurological Syndromes patients; Analysis of PET-scan	Other: PET-Scan analysis; Investigate and determine the clinical value of different cortex/striatal metabolic ratio patterns in each antibody-specific subtype of autoimmune encephalitis

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Ratio metabolic cortex-striatum	Decrease in the metabolic ratio cortex/striatum in included patients, compared to a control reference cohort.	Up to 10 months

Collaborators and Investigators

• Sponsor: Hospices Civils de Lyon

Study record dates

Study Major Dates

• Study Start (Actual): March 1, 2024
• Primary Completion (Estimated): June 1, 2024
• Study Completion (Estimated): December 31, 2024

Study Registration Dates

• First Submitted: May 14, 2024
• First Submitted That Met QC Criteria: May 22, 2024
• First Posted (Actual): May 29, 2024

Study Record Updates

• Last Update Posted (Actual): May 29, 2024
• Last Update Submitted That Met QC Criteria: May 22, 2024
• Last Verified: May 1, 2024

More Information

Terms related to this study

• Keywords: autoimmune encephalitis; auto-antibodies; Paraneoplastic neurological disorders; PET-SCAN
• Additional Relevant MeSH Terms: Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Immune System Diseases; Autoimmune Diseases; Endocrine System Diseases; Thyroid Diseases; Thyroiditis, Autoimmune; Thyroiditis; Neuroinflammatory Diseases; Encephalitis; Autoimmune Diseases of the Nervous System; Hashimoto Disease
• Other Study ID Numbers: 69HCL24_0511

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No