Neuroimaging for central nervous system tumors.

Advances in neuroimaging techniques have now provided clinicians with the ability to detect CNS neoplasms at an earlier stage and to measure responses to therapy. However, errors in performing or interpreting these studies can lead to erroneous conclusions that may subsequently influence therapeutic decisions. The exact delineation of areas of tumor involvement in the brain has improved with newer imaging techniques, but this too is problematic in some patients. Evaluations of response to treatment can also be complicated by technical artifacts that can lead to inadequate differentiation of tumor from non-neoplastic tissues. Nevertheless, MRI and CT have helped clinicians to redefine the natural history of CNS tumors, reach earlier diagnoses, improve the accuracy of radiotherapy, explain adverse treatment responses, and exclude conditions that are not related directly to the tumor but that can be responsible for clinical deterioration. Newer tests that have the ability to assess tumor metabolism will further increase our understanding of these pathological processes.