Bone Marrow Changes in Acute and Chronic Trauma

Abstract

This chapter will discuss the value of medical imaging in the detection and follow-up of bone marrow edema (BME), resulting from acute and chronic trauma. The mechanisms of trauma, clinical significance and natural evolution are emphasized. Unlike plain radiography and computed tomography (CT), magnetic resonance imaging (MRI) is the only imaging technique that allows direct detection of BME. The use of fluid-sensitive sequences is particularly appropriate to evaluate BME. Apart from detection, analysis of the extent of BME may reveal the underlying mechanism of trauma. Following a single acute trauma, compressive forces between two bony structures may result in extensive areas of BME, whereas distraction forces provoke more subtle areas of BME at the insertion of supporting structures of joints. In most clinical situations, a combination of compression and distraction forces is present, causing a complex pattern of BME. A meticulous pattern approach of the distribution of these bone marrow changes around a joint can reveal in most instances the underlying mechanism of trauma. This may be helpful to analyze which joint supporting structures may be at risk. In the acute setting, plain radiography and CT may have an additional role in the detection of small avulsion fractures occurring at the site of minor areas of BME. Apart from an acute traumatic cause, BME may result from repetitive or chronic trauma. This group of lesions comprises stress fractures, chronic avulsive lesions and lesions due to altered biomechanics in certain sports activities. The clinical significance and natural history of BME is still a matter of debate.