What imaging features are typically seen in infections of bones or joint spaces?
In acute osteomyelitis, the earliest radiographic abnormality is soft tissue swelling with obliteration of normal tissue planes. Hyperemia results in osteopenia, and bone destruction or periostitis may not be visualized for 7–14 days. MRI is much more sensitive for detection of early osteomyelitis. MRI is particularly helpful in defining the full extent of osteomyelitis, particularly when amputation is a therapeutic option ( Fig. 8.9 ). Osteomyelitis may be associated with a Brodie’s abscess, usually in the metaphysis of tubular bones in skeletally immature patients. A well-marginated lucent defect (commonly elongated) is seen surrounded by a thick band of sclerosis. With chronic osteomyelitis, radiodense spicules of necrotic bone, referred to as sequestra, may be seen within the lucent defect.
