Dynamic contrast-enhanced MRI for monitoring bisphosphonate therapy in Paget's disease of bone.

Abstract

The purpose of this study was to evaluate changes in regional bone perfusion in Paget's disease (PD) following bisphosphonate therapy. We used dynamic contrast-enhanced MRI (DCE-MRI) for assessment of bone perfusion and compared MRI findings with alkaline phosphatase (AP) as a serum marker of bone turnover. We examined 20 patients (8 women, 12 men, 66 ± 11 years) with symptomatic PD of the axial skeleton. Patients were selected for infusion therapy with the bisphosphonate pamidronate. The most affected bone of lumbar spine or pelvis was examined by DCE-MRI prior to therapy and after a 6-month follow-up. The contrast uptake was evaluated using a two-compartment model with the parameters amplitude A and exchange rate constant K(ep). Color-coded parametric images were generated to visualize bone vascularization. After a 6-month follow-up there was a significant decrease in alkaline phosphatase and in DCE-MRI parameters A and K(ep) (p < 0.0001). Patients without previous bisphosphonate treatment showed a significantly greater decrease in alkaline phosphatase and K(ep) (p < 0.001). DCE-MRI shows a significant reduction in regional bone perfusion in PD following parenteral bisphosphonate treatment. Reduction in bone perfusion is greater in bisphosphonate-naïve patients than in those who had been previously treated.