Comparison of CT and MR imaging in musculoskeletal neoplasms.

Magnetic resonance (MR) and CT of 50 musculoskeletal neoplasms were compared to investigate the relative values of these modalities in the assessment and staging of musculoskeletal neoplasms and to determine how often they are complementary and when they are redundant. The material included 25 benign and 25 malignant neoplasms, of which 33 were skeletal and 17 were of soft tissue origin. Magnetic resonance was superior to CT with respect to all morphologic criteria except for cortical bone destruction, calcification, ossification, and the assessment of lytic and sclerotic changes in flat bones. Magnetic resonance was found to be complementary to CT in 48% of the cases (30% malignant, 18% benign). Use of both MR and CT was considered redundant in 52% of the cases (20% malignant, 32% benign). Magnetic resonance was found to be the modality of choice for all benign and malignant soft-tissue neoplasms. Both modalities are complementary and necessary for complete evaluation of malignant skeletal tumors. Benign skeletal tumors should be considered for evaluation by CT, MR, or both on an individual case basis.