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.
Department of Neuroscience, Uppsala University CSO, Imanet, Uppsala, Sweden. Niklas.Marklund@neurokir.uu.se
Niklas
N
Marklund
Sven
S
Sihver
David A
DA
Hovda
Bengt
B
Långström
Yasuyoshi
Y
Watanabe
Gunnar
G
Ronquist
Mats
M
Bergström
Lars
L
Hillered
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