MR imaging of cerebral tumors: state of the art and work in progress.

MR imaging of the brain has made tremendous progress during the last years. This technique is generally superior to computed tomography (CT) in brain tumors, due to its capability for direct imagining in various planes and its high tissue contrast. Moreover, the detectability and differentiation of extraaxial tumors, previously the domain of CT, has been improved with paramagnetic contrast agents (PCA). Although, the sensitivity of MRI for intracranial tumors is unchallenged, the specificity for such tumors is not remarcably greater than that of CT. Differentiation between high grade glioma, abscess and metastasis still requires biopsy for definitive diagnosis. Methods for improvement of specificity--tissue characterization--are currently being evaluated in a clinical setting. Further development in this field is necessary before such methods can be applied on a routine basis.