Basic principles of nuclear medicine techniques for detection and evaluation of trauma and sports medicine injuries.

Nuclear medicine skeletal imaging is a very sensitive technique for evaluating bone and muscle abnormalities because it can detect minor changes in metabolism and blood flow. The specificity of bone imaging, however, depends on the ability of the nuclear medicine physician to make a differential diagnosis. To aid in making a specific diagnosis, this article describes the various patterns of abnormality in stress fractures, tibial stress syndrome (shin splints), compartment syndrome, enthesopathy, and traumatic fractures. The characteristic scintigraphic appearance of joint injuries, muscle injuries (rhabdomyolysis), and radionuclide arthrography is discussed and the way the scan patterns change with time in these various disorders is described. A brief summary of the basic anatomy and physiology of bone and muscle in normal and injured tissue is presented and the basic mechanisms which cause the various abnormal scan patterns is postulated. In addition, a staging system for stress fractures is presented to help direct the referring physician toward the proper management of the injured patient. In most cases, nuclear medicine skeletal imaging can be used to differentiate between acute muscle injury, tibial stress syndrome, skeletal injury (periosteal reaction, stress fracture, and traumatic fracture) or an abnormality that is entirely associated with the joint or connective tissue. This differential diagnosis is easier if the nuclear medicine procedure is performed within a few days after the onset of injury.