Correlation of multimodality imaging in Paget's disease of bone.

PURPOSE: The aim of this study is double: 1. to review the known and less known radiographic patterns of Paget's disease of bone, employing the most recent imaging techniques; 2. to propose a rationale algorithm for the diagnosis and management of the disease. considering its inconsistency and clinical variability. MATERIALS AND METHODS: Forty-eight patients with Paget's disease of bone (30 males and 18 females, aged 45 and 88 years, mean age 71) were examined in the period 1999-2003. The patients were classified into two groups: symptomatic and asymptomatic. The first group, comprising 32 patients with generic ''low back pain'' with or without sciatica, or ''coxarthritis'' underwent conventional radiography. In the second group (16 patients), bone disease was discovered in course of radiological and/or scintigraphic examinations performed for other conditions. Subsequently, all the patients completed the diagnostic algorithm, consisting of radiographs of the remaining skeletal areas and those segments with abnormal scintigraphic uptake. RESULTS: Monostotic Paget's disease was observed in 31 cases (64.6%), of whom 20 males (64.6%) and 11 females (35.4%), whereas polyostotic disease was found in 17 cases (35.4%), of whom 10 males (58.8%) and 7 females (41.2%). The sites most frequently affected in the monostotic form were: pelvis, 13 cases (43.3%); femur, 5 cases (16.7%); lumbar spine, 5 cases (16.7%); humerus, 2 cases (6.7%); tibia, 2 cases (6.7%); dorsal spine, skull, radius, patella, 1 case respectively (3.3%). In the polyostotic disease (17 cases), the affected bones were predominantly the skull, vertebral spine and pelvis (see text for their variable association). Pathologic fractures of the femur were found in two males. Osteogenic sarcoma (histological diagnosis) developed in the proximal femur in a 81 year-old male. CONCLUSIONS: Paget's disease is asymptomatic in the majority of affected individuals, and may be discovered incidentally with diagnosis being made on routine radiographs obtained for other purposes. Sometimes the x-ray features are so typical that the diagnosis is straightforward. Bone scan should be the imaging technique of choice, because tracer uptake is directly related to degree of activity of disease, and it may advance any radiographic evidence. Vertebral involvement is better evaluated by CT. Both CT and MRI are recommended in spine complications (pathological fractures, radicular or cord compression syndromes, malignant degeneration).