The NMR diagnosis of cerebral tumors.

The results of NMR examinations in 52 patients with histological or clinical diagnoses of cerebral tumor are reviewed. An increase in relaxation time was recognized in all tumors but problems were experienced in distinguishing the margin of tumors from surrounding edema. Mass effects were well demonstrated as a result of the high level of gray-white matter contrast available with inversion-recovery sequences and the use of coronal and sagittal imaging planes. In general repeated FID sequences were less sensitive in detecting tumors than inversion-recovery or spin-echo sequences. Periventricular edema was well demonstrated with spin-echo sequences and was of importance in recognizing acute or subacute hydrocephalus. Radiation therapy was associated with increased relaxation times particularly within white matter. Problems in the recognition of tumor recurrence following treatment are outlined. The opportunities and challenges that NMR imaging is now providing for physicists and radiologists are discussed.