Which statement about diagnostic imaging for osteomyelitis is true?

• A. X-ray is the best diagnostic test
• B. MRI is the best imaging for diagnosis
• C. Ultrasound is superior to MRI
• D. Bone scan is not helpful

Answer: (B)

MRI is the imaging modality of choice for diagnosing osteomyelitis because it directly visualizes bone marrow edema, the earliest and most reliable sign of infection, and can accurately delineate the extent of bone involvement as well as adjacent soft tissue infection, abscesses, and septic arthritis when present. Contrast-enhanced MRI further improves specificity by highlighting infection-related enhancement. X-ray findings lag behind by weeks and are often normal in early disease, so X-ray is not reliable for initial diagnosis. Radionuclide bone scans and ultrasound have roles in certain contexts but are either nonspecific (bone scan) or limited to soft tissue assessment and do not provide the same detail about bone marrow/infection as MRI.