Synovial visualization during Tc-99m MDP bone scanning in septic arthritis of the knee

During Tc-99m medronate (MDP) bone scintigraphy, visualization of the synovium during blood flow and blood pool phases was present in a patient with septic arthritis of the left knee. Inflammation with hyperemia of the synovium was the cause for radionuclide localization, which was enhanced by the large photon-deficient effusion distending the suprapatellar bursa. The synovium was not seen on delayed images after redistribution of the radionuclide from blood pool to bone phase.