Review Question - QID 219000

An 8-year-old male initially presents to the ER with 2 days of worsening knee pain. He tripped and fell during a soccer game the day prior to symptom onset, sustaining an abrasion to his left knee. Temperature on admission was 38.5ºC (101.3ºF), serum white blood cell count 16,000/mm3 (normal 4000-10,000/mm3), and C-reactive protein 22 mg/L (normal 3-10 mg/L). Imaging studies at the time of admission revealed osteomyelitis of the distal femur and he was started on empiric piperacillin-tazobactam. Blood cultures have since returned positive for Gram-positive cocci; speciation and sensitivity tests are pending. However, he continues to complain of pain to the leg 3 days after admission. Temperature is now 38.7ºC (101.7ºF), serum white blood cell count is 17,500/mm3, and C-reactive protein is 26 mg/L. Which of the following imaging studies best represents the underlying diagnosis?