Quantitative bone scintigraphy in Paget's disease treated with APD.

Half-yearly bone scintigrams of 27 patients with Paget's disease, who were treated with the bisphosphonate APD, were evaluated. Uptake of 99Tcm-Sn-EHDP was determined by computer analysis. All patients reached clinical and biochemical remission, usually within 6 months. The scintigraphic uptake dropped steeply during the first 6 months and only slightly during the second 6 months. The decrease in uptake was proportional to the original uptake and averaged 80% of this value. The residual 20% persisted, although clinical and biochemical remission were attained. The scintigraphic results obtained with APD agree with our earlier findings for patients in remission after treatment with a combination of calcitonin and EHDP. Eight patients suffered a recurrence after discontinuation of APD. In all cases scintigraphic deterioration also occurred, usually simultaneously or 6 months before the recurrence. In two patients with scintigraphic deterioration a recurrence could not be confirmed during this study. The scintigraphic deterioration presented as one of the three patterns seen after combination therapy.