Changes in the lumped and transfer rate constants for 2-[18F]fluoro-2-deoxy-D-glucose (2-[18F]FDG) were studied before and 16 hours after bilateral middle cerebral artery (MCA) occlusion in four cats. The time course of cerebral tissue radioactivity [Ci*(t)] in a volume of brain was monitored by external coincidence counting during a programmed infusion of 2-[18F]FDG. The arterial plasma concentration [Cp*(t)] of the tracer was kept constant during the first 45 minutes. The apparent rate constants were estimated from the Ci*(t) and CPp*(t) by a weighted, nonlinear least squares fitting method. The lumped constant (LC) was estimated from the fit of the ratio of extraction fractions of glucose and 2-[18F]FDG by a nonweighted, nonlinear least squares fitting. At 16 hours after MCA occlusion, the k1* was 39% lower, the k2* 19% lower, the k3* 27% lower, and the LC 74% higher relative to the preocclusion values. A 65% reduction in glucose utilization was also observed.