Utility of Combined 99mTc-Phosphate and 67Ga Imaging in Diagnosis of Septic Arthritis

A case of septic arthritis diagnosed by combined 99m Tc-phosphate and 67Ga imaging, which preceded positive cultures of the infecting organism, is presented. A previously healthy 10-year-old girl complained of pain in her left hip with persistent fever. Initial laboratory studies showed a normal white cell count and negative blood cultures. A septic process was not confirmed. Blood flow studies and bone images with 99mTc-phosphate showed markedly increased perfusion in the left hip joint without extension to bone. Subsequent 67Ga images revealed a marked increase in radioactivity in the same region, indicating the presence of a septic process. Serial blood cultures and arthrocentesis showed Staphylococcus aureus. The patient improved on antibiotics.