PT - JOURNAL ARTICLE AU - Naoya Hattori AU - Sung-Cheng Huang AU - Hsiao-Ming Wu AU - Weihsun Liao AU - Thomas C. Glenn AU - Paul M. Vespa AU - Michael E. Phelps AU - David A. Hovda AU - Marvin Bergsneider TI - Acute Changes in Regional Cerebral <sup>18</sup>F-FDG Kinetics in Patients with Traumatic Brain Injury DP - 2004 May 01 TA - Journal of Nuclear Medicine PG - 775--783 VI - 45 IP - 5 4099 - http://jnm.snmjournals.org/content/45/5/775.short 4100 - http://jnm.snmjournals.org/content/45/5/775.full SO - J Nucl Med2004 May 01; 45 AB - During the acute phase after traumatic brain injury (TBI), the metabolic state is regionally heterogeneous. The purpose of this study was to characterize contusional, pericontusional, and remote regions of TBI by estimating glucose transporter and hexokinase activities on the basis of 18F-FDG kinetic modeling. Methods: A standard 2-compartment model was used to measure 18F-FDG kinetic parameters in 21 TBI patients with cerebral contusions studied during the acute phase (3.1 ± 2.1 [mean ± SD] d after injury). Nineteen patients also underwent 15O-water PET to measure regional cerebral blood flow (CBF). A control study (18F-FDG and 15O-water) was done with 18 healthy volunteers. The rate constants Ki, K1, and k3 were assumed to represent the uptake, transport, and hexokinase activity of 18F-FDG, respectively; Ki was calculated as K1 × [k3/(k2 + k3)]. Results: The areas of contusional and pericontusional tissues located 4.5, 13.5, and 22.5 mm away from the contusion (PC4.5, PC13.5, and PC22.5, respectively) demonstrated significantly reduced K1 values, whereas the K1 values for remote areas remained normal. The k3 values were significantly reduced regardless of the distance from the contusion. Pericontusional areas with CT- or MRI-evidenced tissue damage showed significantly lower Ki (P &lt; 0.001), CBF (P &lt; 0.01), and K1 (P &lt; 0.0001) values than did areas without such damage, whereas the k3 values did not differ significantly. Seven patients showed regionally increased 18F-FDG uptake (hot spots) in pericontusional areas. The k3 value for the hot spots (0.086 ± 0.024/min) was significantly higher than that for the remote cortex (P &lt; 0.01), whereas the Ki, CBF, and K1 values did not show significant differences. Patients with hot spots showed significantly higher Ki and k3 values in PC4.5 (P &lt; 0.05) and higher k3 values in PC22.5 (P &lt; 0.05) than did patients without hot spots, whereas the K1 and CBF values did not differ significantly. Conclusion: Brain tissue 18F-FDG kinetics in TBI patients were consistent with reduced hexokinase activity in the whole brain (including apparently uninjured cortex), whereas glucose transport was impaired only in the area immediately around the contusion. Pericontusional high levels of 18F-FDG uptake observed in a subgroup of patients could have been the result of regionally increased hexokinase activity.