Usefulness of functional MRI associated with PET scan and evoked potentials in the evaluation of brain functions after severe brain injury: preliminary results.

ABSTRACT

OBJECTIVE: To evaluate the feasability and the potential usefulness of functional MRI (fMRI) for the evaluation of brain functions after severe brain injury, when compared to a multimodal approach (evoked potentials [EP] and Positron Emission Tomography [PET] examinations). MATERIAL AND METHODS: Seven patients (mean age 49 years [23-73], three males, four females) presenting with coma after acute severe brain injuries underwent fMRI (auditive, visual, somesthesic), (18)F-FDG PET and EP (auditive, visual, somesthesic) within a 3-day period of time in a mean of 120 days after initial brain injury. fMRI activations in somesthesic, visual and auditive cortical areas were compared to EP (28 possible comparisons) and to the metabolic activity on PET examination in the same anatomical areas (21 possible comparisons). RESULTS: In case of availability, results were concordant between fMRI and PET in 10 comparisons but not in one, and between fMRI and EP in 11 comparisons but not in four. CONCLUSIONS: In many patients, there is a good concordance between fMRI and brain functions suggested by EP and metabolic activity demonstrated with PET. In few others, fMRI can be integrated in the early evaluation of brain functions to further augment our capacity for a proper evaluation of brain functions in critically ill patients.