Impact of Confirmed Autoimmune Encephalitis on Brain Glucose Metabolism

Not Applicable

Recruiting

• Conditions: Autoimmune Encephalitis
• Interventions: Other: FDG PET

• Registration Number: NCT06079294
• Lead Sponsor: Assistance Publique - Hôpitaux de Paris

Brief Summary

Prospective cohort study evaluating FDG PET in 56 patients with confirmed autoimmune encephalitis - based on 2016 Graus criteria, and 2021 paraneoplastic neurological syndromes criteria - at the acute phase, before immunomodulating treatment, or within 10 days of treatment initiation.

Detailed Description

Autoimmune encephalitis is a diagnostic challenge, and requires early diagnosis for improved neurological outcomes. FDG PET has shown very high sensitivity, suggesting better performances than MRI, but almost exclusively in small sized retrospective studies. Brain FDG PET is therefore not included in current diagnostic criteria, conversely to brain MRI. This study will include 56 patients with confirmed - seropositive or seronegative - autoimmune encephalitis, based on 2016 Graus criteria for autoimmune encephalitis and 2021 criteria for paraneoplastic neurological syndromes. The main objective is to conduct a prospective evaluation of the diagnostic value of FDG PET performed in the acute phase before treatment initiation, or within 10 days of treatment initiation. A follow-up PET performed 3 months after treatment initiation will also be performed and analysed for all patients as part of secondary objective analyses.

Study Timeline

• Study First Submitted: 2023-10-06
• Study First Submitted QC: 2023-10-06
• Study First Posted: 2023-10-12
• Study Start: 2024-05-31
• Status Verified: 2024-06
• Last Update Submitted: 2024-06-05
• Last Update Posted: 2024-06-06
• Primary Completion: 2026-04-30
• Study Completion: 2026-05-31

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 56

Inclusion Criteria

• Age ≥ 18 years old

• Newly diagnosed autoimmune encephalitis based on at least 1 of the 3 following criteria :

  1. " Definite limbic autoimmune encephalitis " according to 2016 Graus et al. criteria
  2. " Possible autoimmune encephalitis " according to 2016 Graus et al. criteria AND typical autoantibody detected in serum or CSF
  3. " Probable or certain paraneoplastic neurological syndrome " according to Graus et al. 2021 criteria (excluding peripheral neurological syndromes)

• Less than 6 months since first neurological symptoms imputable to autoimmune encephalitis

• Affiliated or entitled to a social security system (except AME)

• Obtaining free, written and informed consent (patient or legal representative or the close relative)

Exclusion criteria

• History of brain tumor, head trauma, infarction or cerebral hematoma likely to result in altered cerebral carbohydrate metabolism on PET
• Patients who hae been on immunotherapy (corticosteroid bolus, IVIg, plasma exchange, endoxan, rituximab or other immunotherapy) fr more than 10 days
• Pregnant or breast-feeding woman
• Ventilated intubated patient
• Absolute contraindication to MRI (Pacemaker, cochlear implant, etc.)
• Presence of cognitive disorders incompatible with goog cooperation with the PET scan
• Algic or agitated patient unable to remain immobile in supine position for 30 minutes
• Deprived of liberty or under a protective measure (guardianship or curatorship)
• Patient taking part in other interventional research involving radiopharmaceutical injections

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Exclusion Criteria

Not provided

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
FDG PET	FDG PET	-

Primary Outcome Measures

Name	Time	Method
Main analysis of initial brain FDG PET	PET performed at the acute phase, before immunomodulating treatment (or within 10 days of treatment initiation)	Automated region-based and voxel wise quantitative PET analysis, estimation of the proportion of patients with PET anomalies (overall and by region of interest).

Secondary Outcome Measures

Name	Time	Method
Analysis of initial whole body FDG PET	PET performed at the acute phase, before immunomodulating treatment (or within 10 days of treatment initiation)	Evaluation of whole body FDG PET diagnostic performance for identifying neoplasms in paraneoplastic syndromes
Analysis of follow-up brain FDG PET	PET performed 3 months after treatment initiation, compared to initial brain PET	Automated region-based and voxel wise quantitative PET analysis comparatively to initial brain PET
Secondary analysis of initial brain FDG PET	PET performed at the acute phase, before immunomodulating treatment (or within 10 days of treatment initiation)	PET voxel-wise connectivity analysis
Secondary analysis of initial and follow-up brain FDG PET	PET performed at the acute phase, before immunomodulating treatment (or within 10 days of treatment initiation), and follow-up PET 3 months after treatment initiation	Correlation of PET treatment response to clinical symptom treatment response

Trial Locations

Locations (1)

Hospital Pitie Salpetriere; 🇫🇷 Paris, France