Abstract
In a series of 10 patients with severe traumatic brain injury FDG PET studies were carried out in an interval of 1-62 months post trauma. They revealed decreased values of glucose metabolic turnover not only in the regions visibly affected on CT and MRI, but also in distant areas of the ipsi- and contralateral hemispheres.
While the global metabolism of the injured hemispheres was decreased to 73% of healthy probands, also the,,unaffected" hemispheres in patients with unilateral lesions were suppressed to 80% of control values. Focal reductions of metabolism in traumatic regions were apparent in 9 cases, reaching a level of less than 20 mumol/100g tissue/min in 7 of them.
In selected homolateral regions of interest beyond the apparent traumatic lesion a decreased metabolism lower than 80% of the contralateral analogous region was found in 6 patients, predominantly in the thalamus and putamen. Surprisingly also selected regions of increased metabolism in the injured hemisphere, compared to the opposite side, were found in 4 patients.
Only in 1, however, did these values surpass those of healthy volunteers. In conclusion, a decreased posttraumatic metabolic turnover is present in homolateral as well as in contralateral brain regions - in areas unaffected by trauma on morphological imaging (CT and MRI).