Bruxism--before and after images--on 18F-FDG PET/CT.

Physical activity before F-FDG PET/CT can cause increased muscle glucose metabolism. We report markedly increased glucose metabolism in the masseter and temporalis muscles of a 53-year-old man who was clenching his teeth before the scan, and then resolution of this increased metabolism on a second scan 12 weeks later. SUVmax in the right masseter muscle was 26.9; 12 weeks later, the SUVmax was 1.6. This level of FDG uptake in bruxism has not yet been reported.