Actively Recruiting
Dopaminergic Disruption Induced by Traumatic Coma: Dopaminergic Pathways Abnormalities and Biomarkers of Recovery Using MRI and 18F-LBT-999 PET
Led by Institut National de la Santé Et de la Recherche Médicale, France · Updated on 2026-05-08
55
Participants Needed
1
Research Sites
189 weeks
Total Duration
On this page
AI-Summary
What this Trial Is About
The neural correlates of consciousness have been studied at the macroscopic level. However, the neurochemical basis of these processes remains poorly understood. The mesocircuit theory challenges the cortico-centric view of consciousness. It highlights the role of subcortical regulation by dopaminergic circuits, including the ventral tegmental area and striatal loops. Experimental data show the importance of dopamine in consciousness recovery. Animal TBI studies link dopamine deficits to loss of consciousness and recovery. In humans, imaging studies show disrupted dopaminergic networks in chronic consciousness disorders. Yet, early-phase dopaminergic disruptions in acute coma remain underexplored. Molecular imaging with PET or SPECT offers insights into dopamine system disturbances. The novel radiotracer 18F-LBT-999 enables detailed imaging of dopaminergic circuits, providing better spatial resolution and quantification than SPECT. This proof of concept study aims to explore acute subcortical dopaminergic loop disruptions. It will combine 18F-LBT-999 PET with structural and functional MRI in post-traumatic coma. Methods : Patients with severe traumatic brain injury (TBI) admitted to the intensive care unit state will be evaluated within 30 days post-injury. Participants will undergo clinical assessment after sedation clearance and will be categorized into three groups: (1) TBI-COMA (severe TBI with persistent coma), (2) TBI-REC (severe TBI with recovery of command-following), and (3) healthy controls. All participants will undergo clinical evaluations, anatomical and functional MRI, and molecular imaging: 18F-LBT-999-PET. Neurological outcome (CRS-r scale), Disability rating scale (DRS), Quality of life (QUOLIBRI) and axtrapyramidal symptoms (MDS-UPDRS) will be assessed at 3 month. Primary Hypothesis: Acute post-traumatic severe TBI patients with persistent coma (TBI-COMA) show reduced presynaptic dopamine receptor levels in the striatum, compared to healthy controls. Secondary Hypotheses: * Dopaminergic disruptions correlate with the severity of consciousness impairment, differentiating TBI-COMA and TBI-REC groups. * Structural damage in the striatum and nigrostriatal tract, identified via MRI, aligns with dopaminergic abnormalities. * Multimodal imaging findings during the acute phase can predict long-term neurological and quality-of-life outcomes. * Characterizing structural, functional, and metabolic variations in dopaminergic networks may guide personalized pharmacological treatments.
CONDITIONS
Official Title
Dopaminergic Disruption Induced by Traumatic Coma: Dopaminergic Pathways Abnormalities and Biomarkers of Recovery Using MRI and 18F-LBT-999 PET
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Aged 18-65 years.
- Affiliated with or beneficiary of a social security system.
- Signed informed consent provided by the participant or a trusted representative (for patients).
- Hospitalized for a non-penetrating traumatic brain injury (TBI) occurring within the last 30 days, with traumatic coma (Glasgow Coma Scale (GCS) < 10 and motor score (M) < 6) at hospital admission.
- Sedative treatments discontinued for more than 48 hours.
- Clinically stable (no hemodynamic, respiratory, or metabolic instability requiring specific interventions that contraindicate medical transfer to the imaging center).
- For the TBI-COMA Group: Severe TBI with prolonged coma, defined as initial GCS < 10 with M < 6, and no recovery of consciousness at inclusion (GCS < 10 with M < 6).
- For the TBI-REC Group: Severe TBI with prolonged coma, defined as initial GCS < 10 with M < 6, with recovery of consciousness evidenced by simple command-following (GCS ≥ 10 with M = 6) at inclusion.
- For Healthy Controls: Matched by age (± 2 years) and sex to patients in the TBI-COMA group.
You will not qualify if you...
- Pregnant or breastfeeding women.
- Contraindications to MRI.
- Known allergy to the PET radiotracer or its excipients.
- History of conditions affecting the dopaminergic system.
- Individuals under legal protection measures.
- Current treatment with dopaminergic agonists or antagonists.
- Coma due to causes other than TBI.
- Decompressive craniectomy causing anatomical alterations incompatible with standardized image analysis (e.g., midline shift > 2 cm).
- For Healthy Controls Only: Women of childbearing potential without effective contraception.
- For Healthy Controls Only: Women unwilling to maintain effective contraception during the 30-day study period.
AI-Screening
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Trial Site Locations
Total: 1 location
1
CHU de Toulouse
Toulouse, France
Actively Recruiting
Research Team
B
BENJAMINE SARTON, MD, PhD
CONTACT
S
STEIN SILVA, MD, PhD
CONTACT
How is the study designed?
Study Type
INTERVENTIONAL
Masking
NONE
Allocation
NA
Model
SINGLE_GROUP
Primary Purpose
BASIC_SCIENCE
Number of Arms
1
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