Magnetic resonance imaging (MRI) has a high sensitivity, specificity, and accurate rates for identification of bone, periosteal, and soft tissue involvements [11]. MRI is useful for identifying early bone marrow changes, osteomyelitis, and subperiosteal or soft tissue collections such as abscesses. On MRI, active inflammation shows decreased signal on T1-weighted images and increased signal in T2-weighted images and fat-suppression sequences (Fig. 3.2), [47]. In T1-weighted images, high signal intensity between the abscess and sclerotic bone marrow, called “penumbra sign,” is characteristic of osteomyelitis. The use of contrast agents is generally not necessary for MRI [11].

Scintigraphy is useful when the infection cannot be localized or multifocality is suspected [13]. The three-phase bone scan is usually performed; it consists of a nuclear angiogram (2–5 s after injection), a blood pool phase (5–10 min after injection), and a delayed phase (2–4 h after injection). In the first two phases, increased uptake can be caused by any inflammation that increased the blood flow. However, the increased uptake in the third (delayed) phase reflects the osteoblastic activity. Tc-99 m methylene diphosphonate and Ga 67 citrate are sensitive agents for detecting bone involvement, but they have a low specificity (Fig. 3.3) [47]. A higher specificity has been shown with Tc-99 m polyclonal human immunoglobulin, Tc-99 interleukin-8, In-111 granulocytes, radiolabeling leukocytes, and monoclonal Fab fragments [21, 25, 44].

Computed tomography (CT) indications for osteomyelitis are lack of availability of MRI or contraindications to MRI, the arrangement of the surgical intervention to debridement of sequestra, and identification of bone damage in chronic osteomyelitis. CT findings of osteomyelitis are increased bone marrow density, periosteal new bone formation, and periosteal purulence.

Ultrasonography usually does not help for the diagnosis of osteomyelitis. It can be used for detection of fluid collections and improve the percutaneous drainage procedures.

Ioannou et al. [24] demonstrated that positron emission tomography-computed tomography (PET-CT) scan may provide useful information in osteoarticular brucellosis. Fluorodeoxyglucose uptakes of infected tissues increased as standard uptake value max values. Sensitivity and specificity of the PET-CT is ranging 94–100 % and 87–100 %, respectively. However, this study has been limited to a small number of patient, and therefore, further studies are necessary to clarify these results. PET-CT is better than the other modalities to show the spread of infection and multifocal lesions in a multisystemic brucellosis disease.