If the 3-phase bone scan is positive with increased activity, also obtaining a white blood cell (WBC) scan and Tc-99m sulfur colloid scan may increase specificity for the evaluation of acute osteomyelitis. Addition of sulfur colloid scan may be considered if results remain equivocal following a WBC and 3-phase bone scans. In cases in which radiotracer uptake is increased on WBC scan and 3-phase bone scans, sulfur colloid imaging will show no corresponding radiotracer uptake in cases of osteomyelitis [15,16]. 3-Phase Bone Scan and WBC Scan Area of Interest In patients with low pretest probability of infection who have a positive 3-phase bone scan, the addition of WBC scan may increase specificity for infection, particularly in the setting of recent surgery or fracture at the suspected site of infection [17]. 3-Phase Bone Scan Area of Interest A 3-phase bone scan can be used to rule out osteomyelitis. However, a positive 3-phase bone scan is nonspecific. A meta-analysis performed by Wang et al [17] showed specificity of only 45% for diagnosis of osteomyelitis, whereas sensitivity was 83%. A 3-phase bone scan is most accurate in the diagnosis of osteomyelitis when bone is not affected by other underlying condition such as osteoarthritis, recent fracture, or recent hardware implantation [18]. Addition of single-photon emission CT (SPECT)/CT may be helpful in localization of acute osteomyelitis [19]. Suspected Osteomyelitis, Septic Arthritis CT Area of Interest CT is insensitive in evaluation of acute osteomyelitis. IV contrast administration is helpful for assessing soft tissue involvement. CT may be most useful in characterizing osseous changes from chronic osteomyelitis including detection of sequestrum. Although the use of IV contrast does not improve diagnostic sensitivity for acute osteomyelitis, it may be helpful in the identification of soft tissue infection such as abscess formation [11].
Suspected Osteomyelitis Septic Arthritis or Soft Tissue Infection Excluding Spine and Diabetic Foot PCAs. If the 3-phase bone scan is positive with increased activity, also obtaining a white blood cell (WBC) scan and Tc-99m sulfur colloid scan may increase specificity for the evaluation of acute osteomyelitis. Addition of sulfur colloid scan may be considered if results remain equivocal following a WBC and 3-phase bone scans. In cases in which radiotracer uptake is increased on WBC scan and 3-phase bone scans, sulfur colloid imaging will show no corresponding radiotracer uptake in cases of osteomyelitis [15,16]. 3-Phase Bone Scan and WBC Scan Area of Interest In patients with low pretest probability of infection who have a positive 3-phase bone scan, the addition of WBC scan may increase specificity for infection, particularly in the setting of recent surgery or fracture at the suspected site of infection [17]. 3-Phase Bone Scan Area of Interest A 3-phase bone scan can be used to rule out osteomyelitis. However, a positive 3-phase bone scan is nonspecific. A meta-analysis performed by Wang et al [17] showed specificity of only 45% for diagnosis of osteomyelitis, whereas sensitivity was 83%. A 3-phase bone scan is most accurate in the diagnosis of osteomyelitis when bone is not affected by other underlying condition such as osteoarthritis, recent fracture, or recent hardware implantation [18]. Addition of single-photon emission CT (SPECT)/CT may be helpful in localization of acute osteomyelitis [19]. Suspected Osteomyelitis, Septic Arthritis CT Area of Interest CT is insensitive in evaluation of acute osteomyelitis. IV contrast administration is helpful for assessing soft tissue involvement. CT may be most useful in characterizing osseous changes from chronic osteomyelitis including detection of sequestrum. Although the use of IV contrast does not improve diagnostic sensitivity for acute osteomyelitis, it may be helpful in the identification of soft tissue infection such as abscess formation [11].