ENCEPHATAIP: Impact of Confirmed Autoimmune Encephalitis on Brain Glucose Metabolism

Sponsor

Assistance Publique - Hôpitaux de Paris (Other)

Overall Status

Not yet recruiting

CT.gov ID

NCT06079294

Collaborator

(none)

Enrollment

Location

Arm

Anticipated Duration (Months)

2.3

Patients Per Site Per Month

Study Details

Study Description

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.

Condition or Disease	Intervention/Treatment	Phase
Autoimmune Encephalitis	Other: FDG PET	N/A

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 Design

Study Type:

Interventional

Anticipated Enrollment :

56 participants

Allocation:

N/A

Intervention Model:

Single Group Assignment

Masking:

None (Open Label)

Primary Purpose:

Basic Science

Official Title:

Impact of Confirmed Autoimmune Encephalitis on Brain Glucose Metabolism : a Prospective FDG PET Study

Anticipated Study Start Date :

Jan 4, 2024

Anticipated Primary Completion Date :

Nov 4, 2025

Anticipated Study Completion Date :

Jan 4, 2026

Arms and Interventions

Arm	Intervention/Treatment
Experimental: FDG PET	Other: FDG PET Brain FDG PET performed 3 months after treatment initiation

Arm

Intervention/Treatment

Experimental: FDG PET

Other: FDG PET

Brain FDG PET performed 3 months after treatment initiation

Outcome Measures

Primary Outcome Measures

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

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)]
Subgroup PET analysis according to autoantibody subtype or seronegative status
Secondary analysis of initial brain FDG PET [PET performed at the acute phase, before immunomodulating treatment (or within 10 days of treatment initiation)]
Correlation of main analysis results to important clinical variables (clinical symptomatology (typology and duration of symptoms), MRI, cerebrospinal fluid (CSF), electroencephalogram (EEG).)
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
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

Eligibility Criteria

Criteria

Ages Eligible for Study:

18 Years and Older

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

Inclusion Criteria:

Age ≥ 18 years old
Newly diagnosed autoimmune encephalitis based on at least 1 of the 3 following criteria :

" Definite limbic autoimmune encephalitis " according to 2016 Graus et al. criteria
" Possible autoimmune encephalitis " according to 2016 Graus et al. criteria AND typical autoantibody detected in serum or CSF
" 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