T1-weighted MR imaging for distinguishing large osteolysis of Paget's disease from sarcomatous degeneration.

<bold>Objective: </bold>To report five symptomatic patients, four with unequivocal Paget's disease and large areas of osteolysis and one patient with presumed osteolytic Paget's disease, evaluated by MR imaging to confirm or exclude a sarcoma.<bold>Design and Patients: </bold>Four men and one woman (median age 74 years) presented with new symptoms of pain. Four of these patients had unequivocal Paget's disease with large areas of osteolysis; one patient presented with large focal osteolysis and no other finding. MR imaging was performed in each case to exclude malignancy in the area of osteolysis.<bold>Results: </bold>Two patients whose MR images showed a low signal abnormality on the T1-weighted sequence corresponding to osteolysis on the radiograph were found to have malignant degeneration. Three patients with osteolytic lesions on T1-weighted MR imaging showed preservation of fat signal in the areas of osteolysis, were not biopsied and have been free of malignant disease for from 12 months to 2 1/2 years. One patient had one area of osteolysis in the iliac bone which showed malignancy and another area of osteolysis which showed preservation of fat signal on the T1-weighted sequence.<bold>Conclusions: </bold>The information obtained from T1-weighted MR imaging sequences performed on patients with Paget's disease who have new symptoms and large areas of osteolysis could reliably be used in the clinical decision-making process between conservative follow-up and biopsy. [ABSTRACT FROM AUTHOR]