What imaging study is most appropriate to evaluate possible vertebral osteomyelitis in a patient with Staphylococcus aureus bacteremia?

• A. Echocardiography
• B. Chest X-ray
• C. MRI of the spine
• D. Abdominal CT

Answer: (C)

In Staphylococcus aureus bacteremia, vertebral osteomyelitis is a key hematogenous complication that needs prompt, precise detection. The imaging test chosen should reveal marrow inflammation and any spread to surrounding structures. Magnetic resonance imaging of the spine with gadolinium contrast is the most sensitive and specific way to diagnose vertebral osteomyelitis early, showing marrow edema in the involved vertebrae, disc involvement, and potential epidural or paraspinal abscesses. It also defines the extent of disease and informs treatment decisions, including whether surgery might be needed. Other imaging options like chest X-ray or abdominal CT don’t assess the spine, and echocardiography is used to evaluate heart involvement rather than vertebral infection. Hence, MRI of the spine is the best choice.