The use of a whole body index with bone scintigraphy to monitor the response to therapy in Paget's disease

Bone scintigraphy has long been used to assess Paget's disease and investig ate the response to therapy. Objective visual assessment is, however, diffi cult. The aim of this study was to derive, from a bone scintigram, an index which objectively measured the extent and severity of Paget's disease in t he entire skeleton. This whole body index would provide a single numerical value which could be used to monitor the response to therapy in both monost otic and polyostotic disease. Comparison with other methods of assessing th e condition, such as biochemical markers and pain scores, would also be pos sible. The whole body index was developed and used to retrospectively analy se 80 bone scintigrams on 40 patients. The majority of patients (36) receiv ed treatment with a bisphosphonate between the two scintigrams. Whole body index was compared with serum alkaline phosphatase measured at the same tim e; a significant correlation was found (before treatment P = 0.001, after t reatment P < 0.001). The change in whole body index and alkaline phosphatas e following treatment with various bisphosphonates was also investigated an d a significant correlation found (P < 0.001). Whilst performing the analys is it was also noted that the increase in uptake of the radiopharmaceutical was significantly greater in the cortical long bones than in the trabecula r axial skeleton. This study suggests that a whole body index may be a suit able tool for assessing the response to treatment in Paget's disease. ((C) 2001 Lippincott Williams & Wilkins).