Imaging of Paget's Disease of Bone.

Paget's disease is a metabolic bone disorder affecting the elderly and characterized by bone resorption followed by compensatory bone formation. Radiography is the imaging modality of choice for the diagnosis whereas bone scintigraphy helps stage the extent of the disease and assess response to treatment. MRI and CT are important imaging methods in the assessment of complications and surgical planning. Osteolytic lesions of Paget's first phase present with well-defined margins on radiographs, most commonly in the femur, pelvis, and skull. Cortical thickening, trabecular coarsening, bone marrow sclerosis, and deformities of long bones are present in the mixed- and late-sclerotic phases.