[The clinical relevance of FDG-PET imaging in severe traumatic brain injuries]

To evaluate the usefulness of positron emission tomography (PET) as a predictor of long-term disability after a severe traumatic brain injury (TBI).

Fifty-six patients who had sustained a severe TBI were assessed with a broad battery of cognitive and functional scales at baseline and 6-months after inclusion in a multidisciplinary rehabilitation program. All patients underwent a FDG-PET at baseline. A physician blind to clinical data performed a semiquantitative analysis (normal vs altered) of functional neuroimaging (PET), including four cortical and three subcortical areas. The total number of lesions (cortical, subcortical and total) was correlated to the intensity of the TBI and to clinical data at admission and at follow-up.

All patients showed changes in cerebral metabolism, being the thalamus the area most frequently affected. The degree of cerebral hypometabolism showed a significant correlation with TBI severity, functional disability, global outcome and cognitive impairment not only at baseline but also at follow-up.

According to our results, FDG-PET may be a useful tool when studying brain dysfunction after severe TBI. FDG-PET findings correlate with the TBI severity, and with the level of patients' disability, as well as with the degree of memory and intelligence impairment. However, clinical variables related to the severity of the TBI, still are the best predictors of functional outcome after TBI.