If MRI is unavailable for evaluating suspected osteomyelitis, which alternative imaging modality is commonly used?

• A. Radionuclide bone scan
• B. MRI
• C. CT scan
• D. X-ray

Answer: (A)

When MRI isn’t available, a radionuclide bone scan is commonly used because of its high sensitivity for detecting osteomyelitis and its ability to survey the entire skeleton. In early infection, X-rays and CT often miss changes because bone destruction and periosteal reaction take time to develop. The bone scan, typically using technetium-99m, highlights areas of increased osteoblastic activity, which occur with infection before structural changes are visible on other imaging. This makes it a practical screening tool to localize infection and assess the extent, especially when MRI can’t be obtained. If specificity is a concern, adding a labeled leukocyte scan or using SPECT/CT can help distinguish infection from noninfectious inflammation and improve localization.