FLUORINE-18-FDG PET IN PAGETS-DISEASE OF BONE

Paget's disease of bone is common in the elderly and is associated wit h increased osteoblastic and osteoclastic activity at affected sites i n the skeleton, It is not known whether this high metabolic activity i s associated with increased glycolysis and, hence, uptake of [F-18]FDG , The appearances of Paget's disease with [F-18]FDG PET have not been described and it is not known whether Paget's may cause false-positive studies in those undergoing oncological staging or whether [F-18]FDG PET can reliably differentiate benign pagetic change from osteosarcoma that may complicate Paget's disease. We reviewed [F-18]FDG PET scans in patients with uncomplicated Paget's disease and documented its appe arances, Methods: Eighteen patients with established Paget's disease a nd typical radiological features had Tc-99m-MDP bone scans and [F-18]F DG PET scans performed, Serum alkaline phosphatase (ALP) was also meas ured. Results: All patients showed high uptake of MDP in affected bone s. Of the 18 patients only six showed any uptake of [F-18]FDG. This oc curred in some but not ail bones shown to be involved on MDP bone scan s, Three patients demonstrated low-grade uptake and three showed marke d accumulation of [F-18]FDG. The [F-18]FDG-positive group had higher s erum ALP levels than the [F-18]FDG-negative patients (p < 0.05). Concl usion: Paget's disease of bone is not associated with abnormal [F-18]F DG uptake in the majority of patients and, therefore, there is potenti al for discriminating between benign Paget's disease and associated Pa get's sarcoma. However, low-grade uptake may be seen in patients with more active disease as measured by ALP, Rarely, marked uptake of [F-18 ]FDG may be seen and Paget's disease should be included as a possible cause of false-positive scans in elderly patients who are being assess ed for metastatic disease.