FIGURE 4. AHO with subperiosteal and intraosseous abscess. (A) Angiographic-, tissue-, and skeletal-phase images show high tracer localization and uptake in distal right tibial metaphysis of 11-y-old boy. (B) After fever and pain continued through 3 d of intravenous antibiotic therapy, MRI was requested to assess for suspected abscess. Sagittal gadolinium-enhanced fat-suppressed T1-weighted MR image shows focal intraosseous nonenhancing areas (short arrows) and periosteal elevation with nonenhancing subperiosteal collection (long arrow). Findings indicated intraosseous and subperiosteal abscesses, which were subsequently drained surgically.