Bone scintigraphy and radiology in Paget's disease of bone: a review.

Since effective treatment of Paget's disease is now feasible, knowledge of the possibilities of diagnostic imaging, especially the changes in these images induced by treatment, has become essential. Some forms of treatment may lead to radiographic improvement, indicating that the macroscopic bone texture is changing; radiological imaging, however, is painstaking and liable to technical errors. Different information is derived from the bone scintigram, which is a good monitor of the local bone metabolism and often a sensitive means of identifying lesions. Some parts of the skeleton appear to be affected more often than others, and the likelihood that a bone is involved depends on its size and the proportion of bone marrow. Local scintigraphic uptake appears to correlate with the grade of radiological deformation and the frequency of pain; the total skeletal uptake correlates with the severity of the biochemical abnormalities. Evidently, the metabolic activity of a lesion plays a major role in the occurrence of deformation and the development of pain. Lesions not visible on the radiograph (about 15%) usually show low uptake and are asymptomatic. During successful treatment the scintigram improves impressively, but in remission 20% of the original uptake is retained due to persistent structural abnormalities. Recurrence is accompanied by deterioration of the scintigram. Radiology and scintigraphy offer valuable additional information that confirms the supplements and supports the clinical and biochemical evaluation.