Imaging of the Neural Correlates of Arousal and Awareness

Summary

In last decades, several advances in the neuro-intensive management have lead to decrease mortality in Intensive Care Units. A significant morbidity remains as patients survive after a traumatic coma with uncertain quality of awakening and a high risk of functional disability. Predicting awareness recovery and functional disability of those who will awake constitutes a major challenge to inform patients' relatives, to give the best chances in terms of rehabilitation resources or to adapt intensive cares to a reasonable level. Tools currently available are not sufficient neither to predict bad awakening outcome nor to predict good functional outcome. In many countries, life's support cessation is a constant call for robust evaluation as soon as possible in ICU but it is mandatory to reach a positive predictive value of non-awaking close to 100%. Many clinical, electro-physiological, biological, radiological and functional parameters have been conducted with comatose patients assuming the purpose to predict outcome. Regarding unfavourable outcome, the gold standard is the abolition of the N20 component of somatosensory evoked potentials but the specificity is high enough only for patients with anoxic coma. Several neurophysiological markers such as MMN, P300 are correlated to a favourable outcome but the sensitivity and specificity remains low for patients who suffered a severe traumatic brain injury. New Diffusion Tensor imaging sequences provide complementary information to detect small structural lesions (diffuse axonal lesions). Recently, functional MRI analyzing Resting State has also been proposed as a prognostic marker during coma. PET using Fluoro-Desoxy-Glucose is able to assess the metabolism in key regions of the awakening network in either anaesthesia or sleep. Recent studies have reported interesting results at the chronic stage but to our knowledge, these tools have only been used to address pathophysiology's issues and never to improve coma prognosis at the initial stage. We hypothesize that the heterogeneity of the population requires a global and accurate assessment of the central nervous system, combining structural, metabolic and functional information in order to refine the prognosis.

Our protocol integrates in one-sequence most radiological markers of brain injury within a unique PET-MRI in Lyon. Our most relevant originality consists in confronting FDG-PET and MRI sequences to a large clinical, electrophysiological and biological battery. The added clinical value would be to question the synergistic effect of each parameter and to find out which ones are the most useful for awakening prediction, as they have not been compared in a multi-parametric database.

PET-MRI, as a new device combining physiological and prognostic questioning, allows us:

* to implement a more integrative physio-pathological analysis
* to avoid the cofounding effect of awareness' fluctuations in recording simultaneously multiple functional imaging techniques.

The RS will be analyzed at 2 epochs in order to assess the stability of brain connectivity, related to neuronal activity (glucose metabolism) and brain perfusion.

The interest of imaging result will be compared across morphological and functional sequences and in comparison, to classical marker (clinical, electrophysiological and behavioural) to build the most precise prognostic tool for acute comatose patients in ICU or diagnostic/prognostic tool for chronic patients in rehabilitation unit.

Conditions

• Lesional Coma

Interventions

OTHER

Multimodal evaluation of brain function : PET-MRI, electrophysiology, eye-tracking

After 2 days of sedation withdrawal, each data should be collected within 3 days for organisation purposes : 1. After installation and movement management with standardized routine care protocol: 18Fluoro-Desoxy-Glucose's infusion for PET 2. Starting PET continuous acquisition 3. Morphological MRI sequences 4. MRI in Resting state N°1 5. MRI DTI acquisition 6. IRM in 2D-Arterial Spin Labelling 7. IRM in Resting state 2 8. End of PET continuous acquisition The day before or the day after PET-MR: standard 20 min EEG, somaesthetic evoked potentials, auditory evoked potentials, mismatch negativity, P300 oddball paradigm, local-global paradigm, P300 after music stimulation, EEG resting state for 10 min, CRS-R repeated before each examination (and at least 5 times for chronic patients), eye-tracking study of the environmental exploration.

Sponsors & Collaborators

• Hospices Civils de Lyon

  lead OTHER

Principal Investigators

• FLORENT GOBERT, MD · Hospices Civils de Lyon

Study Design

Allocation

NA

Purpose

OTHER

Masking

NONE

Model

SINGLE_GROUP

Eligibility

Min Age

18 Years

Max Age

75 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2020-11-15

Primary Completion

2020-11-15

Completion

2025-11-15

Countries

• France

Study Locations