ABSTRACT
PURPOSE: 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. MATERIALS AND METHODS: 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. RESULTS: 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). CONCLUSION: 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.
Subject(s)
Diphosphonates/administration & dosage , Gadolinium DTPA , Magnetic Resonance Imaging/methods , Osteitis Deformans/diagnosis , Osteitis Deformans/drug therapy , Aged , Aged, 80 and over , Bone Density Conservation Agents/administration & dosage , Contrast Media , Female , Humans , Male , Middle Aged , Prognosis , Reproducibility of Results , Sensitivity and Specificity , Treatment OutcomeABSTRACT
Aseptic osteonecrosis appears to be an infrequent adverse event after kyphoplasty which has not previously been reported. In the following, we present the case of a 73-year-old female who sustained a compression fracture of the first lumbar vertebra (L1) in a motor vehicle accident. The fracture was treated by kyphoplasty using PMMA cement. Three weeks after hospital discharge the patient was presented with increasing back pain. In imaging, dislocation of the PMMA cement could be shown combined with a total collapse of the L1 vertebra. The resulting significant kyphosis was first reduced by dorsal transpedicular (Th12-L2) internal fixation and stabilized by an anterior cage after total removal of the cement plomb and some remaining bone of the L1 vertebra. Bacterial as well as histological examination of the cement and bone led to the diagnosis of aseptic osteonecrosis. Different underlying events could be discussed. We think it most likely that the osteoporotic bone was unable to interface sufficiently with the PMMA cement and, therefore, disintegrated under loading. Furthermore, the volume of injected cement could have significantly compromised the blood supply within the bone.
