Special report

Osteomyelitis is inflammation of the bone that is usually due to infection. There are different classification systems to categorize osteomyelitis. Traditionally, it has been labeled as acute, subacute or chronic, depending on its clinical course, histologic findings and disease duration, but there is no consensual agreement on the temporal scale used or specific findings. As a result, some researchers have proposed more detailed classification systems, such as the Waldvogel classification system based on etiology of the infection (hematogenous spread of an organism, direct inoculation of an organism through trauma or contiguous spread from a soft tissue infection), and Cierny-Mader classification, a descriptive system that takes into account both anatomic factors and the host’s physiologic status [1,2]. An inadequate or late diagnosis increases the degree of complications and morbidity; for these reasons, imaging techniques are essential to confirm the presumed clinical diagnosis and to provide information regarding the exact site and extent of the infection process [1]. Although a variety of diagnostic imaging techniques is available for excluding or confirming osteomyelitis, it is often difficult to choose the most appropriate technique to conclusively establish the diagnosis of osteomyelitis. Several imaging modalities have been used in the evaluation of suspected osteomyelitis. The ideal imaging technique should have a high sensitivity and specificity; numerous studies have been published concerning the accuracy of the various modalities in diagnosing chronic osteomyelitis [2–4]. Confirmation of the presence of osteomyelitis usually entails a combination of imaging techniques. Table 1 shows the main pathologic findings of osteomyelitis assessed by diverse imaging techniques.