Magnetic resonance imaging of osteosarcomas. Comparison with computed tomography.

This study was done to describe the magnetic resonance imaging (MRI) characteristics of osteosarcomas and to determine the clinical usefulness of MRI in the evaluation of patients with these tumors. Ten patients with osteosarcomas were examined with a Picker MRI scanner (0.15 Tesla resistive magnet). All had computed tomograms available for comparison. For demonstrating tumor extent in marrow, MRI was superior to computed tomography (CT) in 60% and about equal to CT in 40%. For defining soft tissue mass, MRI was superior to CT in 40% and about equal to CT in 60%. Direct sagittal and coronal images on MRI and superior contrast differences between tumor and normal tissues with MRI were the reasons for the advantage of MRI in these instances. CT was superior in all cases for demonstrating calcifications. Overall, MRI is better than CT for defining local extent of osteosarcomas. It is of greatest value in the peripheral skeleton, in the medullary canal, and in soft tissues.