This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Radiology
[{'content': 'X-ray finding of ostemyelitis within 8 day is: \nSelect and explain. \nA. Cystic swelling, B. Soft tissue swelling, C. New bone formation, D. Seyuestrum formation', 'role': 'user'}, {'content': 'Answer: B \nExplanation: B i.e. Soft tissue swelling Radiological features of Acute osteomyelitis: < 7 days Soft tissue swellingQ > 10 days Periosteal reactionQ After 2-6 weeks Lytic changesQ when 50-75% of bone density has been lost', 'role': 'assistant'}]