Assessment of Structural Brain Changes Related to Anoxic Coma Using High-field and Very Low Field Mobile MRI

Condition(s) studied

Investigational drug(s) / intervention(s)

High-field and very-low-field MRI acquisitions: MRI will be early acquired, as soon as possible after patient hospital admission and always in coma state for patients. For both patients and controls each MRI scanning session will encompass pairs of HF and VLF MRI acquisitions, that will be collected the same day. The main MRI sequences will be: T1, T2, FLAIR and DWI. The VLF spatial resolution recommended by the constructor for all these sequences correspond to voxel size is around 1.5mm/1.5mm/5mm. The total brain scanning time is estimated at 30 minutes.

Study summary

Standard predictors of outcome after cardiac arrest (CA) have substantial limitations in terms of reliability and generalizability. By providing brain structural connectivity maps, or connectomes, advanced MRI techniques, operating through high-strength magnetic field (HF; 1.5 to 3-T), have precisely revealed white and grey brain matter damages induced by CA, and have demonstrated the high sensitivity and specificity of these indicators for predicting neurological outcome after CA. However, HF MRI requires rigid safety precautions, highly trained technicians and patient transport to dedicated hospital imaging suites, hindering the implementation of these promising neuroimaging techniques in the setting of critical illness.

Interestingly, a recent report demonstrates the capability of a proof-of-concept very low-field (VLF; 0.064-T) mobile MRI to obtain neuroimaging at the bedside in critically ill patients. Nevertheless, the spatial resolution of VLF-MRI seems low and there is no available evidence about the use of VLF-MRI to extract highly needed new predictors of neurological recovery based on critical brain structural connectomes.

The CUBE project holds the promise of providing a radical paradigm shift in the field of neuroprognostication of anoxic coma patients. The current proposal is a "proof-of concept" study which aims to compare for the first time, HF, VLF and enhanced VLF (recon-VLF) structural connectomes from anoxic coma patients and healthy subjects across the time (3 paired HF and VLF brain scan across the first two weeks after CA). To obtain recon-VLF data, the Investigators will use an ensemble of ground-breaking methods to increase the native spatial resolution of VLF-MRI data. The whole brain imaging dataset will be used to prepare future neuroprognostication studies based on fully bedside assessment of brain structural integrity after CA.

Eligibility

Primary outcome measure(s)

• Differences between whole-brain white (WWM-FA) and grey (GMM) matter global metrics independently acquired by HF and VLF-MRI scans very early after coma onset (D0) — Day 0
  White matter will be assessed by computing the White Matter Fractional Anisotropy (WWM-FA), which ranges from 0 to 1 with lower values related to worse outcomes. Grey matter will be evaluated using Global brain Matter Morphometry (GMM), which encompass both cortical thickness (mm) and deep grey matter volumetry (mm3) assessments, with lower values being associated with poorer outcomes. Both WWM-FA and GMM data will be normalized using brain MRI data obtained from healthy controls (z-scores).

Trial sites (1)

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