MR recognition of supratentorial tumors.

Eighty patients with intrinsic tumors of the cerebral hemispheres and thalami were studied with a 0.5 T superconducting system and third- or fourth-generation computed tomographic (CT) scanners. Twenty-eight patients had histologically verified gliomas, 34 were presumed to have primary brain tumors on clinical grounds, 13 had metastases, and five were postoperative. Lesions shown on CT were equally well demonstrated on magnetic resonance (MR) imaging; more metastases were seen on MR than on CT images. MR revealed abnormal signals in 10 cases in which CT findings were equivocal. It was not possible to differentiate edema from tumor in many cases using the MR imaging sequences currently available. The histologic types of the tumors could not be determined from the MR appearances.