Sequential use of radiophosphate and radiogallium imaging in the differential diagnosis of bone, joint and soft tissue infection: quantitative analysis.

A quantitative analysis of the results obtained by sequential 99mTc methylene diphosphonate (MDP) and 67Ga-citrate (Ga) imaging to disclose and distinguish infections in bone, synovium and adjacent soft tissue is reported. There were 129 patients with proved or probable osteomyelitis, septic arthritis and cellulitis, and 94 patients who were eventually shown to be free of sepsis, but not necessarily free of some other nonseptic affliction. Of the 159 patients referred with a presumptive clinical diagnosis of osteomyelitis 94 were eventually shown to be free of infection. The results of this group by sequential imaging were true positive 0.72, true negative 0.86 and accuracy 0.80 when low-grade Ga uptakes, which were similar in distribution to MDP, were excluded. In 26 patients with septic arthritis, the true-positive fraction for combined MDP and Ga was 0.84. The true-positive fraction for Ga in 38 patients with cellulitis was 0.79.