Increased cerebral uptake of [18F]fluoro-deoxyglucose but not [1-14C]glucose early following traumatic brain injury in rats.
Following experimental and clinical traumatic brain injury (TBI), the local cerebral metabolic rate of glucose (lCMR(Glc)) is commonly estimated using the 2-[(18)F]fluoro-2-deoxy-D-glucose (FDG) method. The adequate estimation of lCMR(Glc) using FDG requires a correction factor, the lumped constant (LC), to convert FDG net uptake into lCMR(Glc). The LC, and thus lCMR(Glc) calculations, require a steady-state that may be disrupted following TBI. In the present report, we hypothesized that [1-(14)C]glucose uptake would accurately reflect glucose dynamics early post-injury, and was compared to the regional uptake of FDG in 44 rats subjected to moderate (2.4-2.6 atm) lateral fluid percussion brain injury (FPI) or sham injury. Cortical energy state and adenylate (ATP, ADP, and AMP) levels were also measured. Early (7-42 min) after FPI, FDG uptake was increased in the ipsilateral cortex and hippocampus (p < 0.05). In contrast, no change in [1-(14)C]glucose uptake (7 and 17 min post-injury) or cortical adenylate content (42 min post-injury) was observed. At 12 h following FPI, the ipsilateral FDG and [1-(14)C]glucose uptake were decreased in the cortex and hippocampus, and the ipsilateral cortical ATP concentration was decreased in comparison to sham-injured controls (p < 0.05). Under the present experimental conditions, the rate of cerebral uptake of FDG and of [1-(14)C]glucose differed, and indicated that following TBI, regional changes in the LC may occur in the immediate, but not in the late, post-injury phase. These results should be considered when interpreting results obtained using FDG for the estimation of lCMR(Glc) early following experimental TBI.
Marklund
Niklas
N
Department of Neuroscience, Uppsala University CSO, Imanet, Uppsala, Sweden. Niklas.Marklund@neurokir.uu.se
Sihver
Sven
S
Hovda
David A
DA
Långström
Bengt
B
Watanabe
Yasuyoshi
Y
Ronquist
Gunnar
G
Bergström
Mats
M
Hillered
Lars
L
D000818:Animals; D001345:Autoradiography; D001930:Brain Injuries / Q000378:metabolism*; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000378:metabolism*; D004734:Energy Metabolism; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism*; D006624:Hippocampus / Q000378:metabolism*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D018709:Statistics, Nonparametric; D013997:Time Factors
D019788:Fluorodeoxyglucose F18; D005947:Glucose