Imaging of tumors of the central nervous system.

Research in diagnosing and understanding brain tumors in neuroradiology is influenced by the investigative tools available to neuroradiologists. CT has represented the gold standard for the past two decades. The role of angiography has become complementary; relevant in the therapeutic phase of embolization of meningiomas or base of the skull tumors or in intra-arterial chemotherapy for gliomas. In 1991, the MR imaging revolution continues to provide new insights in the diagnosis, classification, and understanding of the biology of brain tumors. Interest has been focused mainly on information provided by MR imaging and MR spectroscopy. Spectroscopy is being used in a more systematic way and in large series with different histologic tumor types. Spectra from tumors are definitely different from those of normal brain, although no specific patterns for histologic types were found, with the possible exception of meningiomas. Comparison with positron emission tomography is considered to be useful. Analysis of rare tumors using MR imaging allows better understanding, classification, diagnosis, and surgical therapy of lesions such as central neurocytomas, hamartomatous tumors, and lymphomas. An attempt at a better classification for brain tumors was proposed and may prove to be very useful for systematization and communication.