Osteomyelitis: diagnosis with In-111-labeled leukocytes.

In a retrospective review, 485 patients with suspected osteomyelitis were studied. Of these, 453 patients were studied with both bone and indium-111 leukocyte scanning (173 sequentially and 280 simultaneously). The ability to determine that the infection was in bone rather than in adjacent soft tissue was greater with simultaneous bone scan and In-111 leukocyte studies than with sequential studies. The locations of suspected osteomyelitis were divided into central (containing active bone marrow), peripheral (hands and feet), and middle (between central and peripheral). Specificity remained high (about 90%) regardless of the location. Overall sensitivity was significantly lower in the central location than in the peripheral or middle location. Determination of whether the In-111 leukocyte activity was in bone or adjacent soft tissue was also more difficult when the infection was in the central location. For acute osteomyelitis, sensitivity was high regardless of the location. For chronic osteomyelitis, sensitivity was lower in the central location.