A radiograph often will not demonstrate any changes apart from soft tissue thickening in cases of osteomyelitis and septic arthritis. Changes may only be seen 10-14 days after onset in adults.
A bone scan is a very sensitive study for osteomyelitis. The typical appearance is increased activity in the same location on all 3 phases (dynamic flow, blood pool and delayed). Other differentials would include inflammatory arthopathies, acute fracture and osteitis deformans from Paget disease. Uptake on the bone may persist for many months to years even if the infection has been adequately treated.