Diagnosis of Inflammatory Bone Diseases

For the early diagnosis of skeletal infections, the combined and coordinated efforts of the clinician and imaging specialist are crucial. Successful early diagnosis results in prompt treatment, which in turn may reduce morbidity. This chapter focuses on the complexities surrounding this clinical question. Knowledge of the pathophysiology of skeletal infection, as well as of the strengths and limitations of the multitude of imaging modalities available, aids clinicians in making a timely diagnosis. Information regarding the location of a suspected infection, the patient’s age, and the history of other conditions such as diabetes, arthritis, trauma, and prior surgery needs to be available to nuclear medicine physicians and radiologists. These factors will affect the choice of optimal imaging modality. For any suspected skeletal infection, the initial modality is the standard radiograph. If this simple and inexpensive diagnostic test is not conclusive, other modalities should be considered, particularly bone scan. Currently, magnetic resonance imaging (MRI) or a combination of bone and gallium scanning is the modality of choice for spondylodiscitis. Infection of the diabetic foot is best imaged with combined (preferably simultaneous) bone- and white blood cell–labeled scintigraphy, best using SPECT/CT when available. Bone scans for suspected neonatal osteomyelitis have been found to be sensitive and specific for diagnosis. Advances in imaging technology, such as positron emission tomography (PET) and antibody labeling, provide other options, which improve the speed and accuracy with which osteomyelitis can be diagnosed. Utilizing the techniques widely used currently, an algorithm for the diagnosis of skeletal infection which incorporates the abovementioned variables and complicating conditions is presented.