The correlation between cerebral glucose metabolism and benzodiazepine receptor density in the acute vegetative state.
This paper compares the results of parallel positron emission tomography (PET) studies of regional cerebral glucose metabolism with the radiotracer 18F-fluorodeoxyglucose (FDG) and benzodiazepine receptor (BZR) density by PET using the BZR ligand 11C-flumazenil (FMZ), a tracer of neuronal integrity, in nine patients with acute vegetative state (AVS, duration <1 month). Overall glucose utilization was significantly reduced in AVS in comparison with age-matched controls (global metabolic rate for glucose 26 micromol/100 g/min in AVS vs. 31 micromol/100 g/min in controls). FMZ-PET demonstrated a considerable reduction of BZR binding sites in all cortical regions that grossly corresponded to the extent of reduction of cerebral glucose metabolism assessed with FDG-PET, whilst the cerebellum was spared from neuronal loss. In controls, cortical relative flumazenil binding was not lower than five times the average white matter activity, whilst in AVS, nearly all values were below this threshold. There was no relevant overlap of the data of relative flumazenil binding between both groups. The comparison of FDG- and FMZ-PET findings in AVS demonstrates that alterations of cerebral glucose consumption do not represent mere functional inactivation, but irreversible structural brain damage.
Rudolf
J
J
Klinik für Neurologie der Universität zu Köln, and Max-Planck-Institut für Neurologische Forschung, Köln, Germany.
Sobesky
J
J
Ghaemi
M
M
Heiss
W-D
WD
D000208:Acute Disease; D000368:Aged; D001665:Binding Sites; D001921:Brain / Q000378:metabolism*; D002250:Carbon Radioisotopes; D035061:Control Groups; D005260:Female; D005442:Flumazenil / Q000493:pharmacokinetics; D019788:Fluorodeoxyglucose F18; D018757:GABA Modulators / Q000493:pharmacokinetics; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018458:Persistent Vegetative State / Q000000981:diagnostic imaging / Q000378:metabolism*; D019275:Radiopharmaceuticals; D011963:Receptors, GABA-A / Q000378:metabolism*; D014055:Tomography, Emission-Computed
D002250:Carbon Radioisotopes; D018757:GABA Modulators; D019275:Radiopharmaceuticals; D011963:Receptors, GABA-A; D019788:Fluorodeoxyglucose F18; D005442:Flumazenil; D005947:Glucose