MRI and CT evaluation of primary bone and soft-tissue tumors.

Twenty-six patients with primary tumors of bone or somatic soft tissues underwent both magnetic resonance imaging (MRI) and computed tomography (CT); 15 of the patients had radionuclide bone scans as well. Only in a minority of cases did these tomographic methods provide information needed for diagnosis that could not be derived from the plain radiographs alone; however, for assessing the extent of the disease, both CT and MRI proved very valuable, particularly MRI. Specifically, MRI was superior to CT in delineating the extent of the neoplasms and their relation to surrounding structures in 21 of the patients, equal in four, and inferior in only one. Furthermore, in the 13 patients with tumors of long bone, MRI was judged superior to CT in visualizing marrow abnormality in 12 cases, and equal in only one case. Radionuclide scans demonstrated the lesions in 14 of the 15 cases; its primary utility was in excluding additional lesions. It is concluded that for these patients, MRI was the imaging method of choice in assessing the extent of bone and soft-tissue tumors.