Bone scan: Indium-WBC correlation in the diagnosis of osteomyelitis of the foot

A retrospective study was performed of 20 podiatric cases using technetium-99m methylene diphosphonate three-phase bone scans along with indium-111 oxine leukocyte scans, as needed, to determine the presence and extent of osteomyelitis of the foot. Using criteria developed at our institution, the authors attempt to provide a mechanism to make a reliable diagnosis for osteomyelitis that has been supported by surgical/pathologic confirmation of long-term clinical follow-up. The sensitivity, using bone scans alone, was 100%, and specificity was 47%. Correlating bone and indium-111 leukocyte scans yielded a sensitivity of 100% with a specificity raised to 81%. Indium-111 leukocyte scans were used in 40% of cases when a definitive diagnosis for osteomyelitis could not be made on the basis of the three-phase bone scan or clinical presentation alone. Indium-111 leukocyte scans were also helpful in delineating the extent of the disease process. The authors present a standard technique for a 5-hour delayed imaging in the three-phase bone scan, as well as marking the foot in the indium-111 leukocyte scan with three routine views obtained for each imaging procedure, to ensure clinical accuracy