Brain tumors in children. I. Advances in diagnosis.

This article emphasizes the contributions that new diagnostic techniques have made toward the management of children with brain tumors. The development of computerized tomographic (CT) scanning has revolutionized both the diagnosis and management of patients with brain tumors and has obviated the previously inevitable delays in diagnosis. The development of magnetic resonance imaging (MRI) has certainly facilitated diagnosis of brain tumors in certain locations with the brain, but it remains unproven in other locations. It is clear that at least some of the early promise of MRI scanning has not been realized. Neither CT nor MRI are able to provide functional detail within the brain, nor are they able to differentiate tumor from peritumoral edema to better delineate the tumor margins. It is hoped that the currently experimental techniques of Positron Emission Tomography (PET) scanning and contrast-enhanced MRI scanning will provide such information in the near future. Neurophysiologic methods of assessing brain tumors merit greater consideration than has been afforded to date. Sensory evoked-potential monitoring provides information about nervous system function. This information is useful both in diagnosis and in monitoring of brain tumors, since the functional information can be localized to discrete regions within the brain. The value of cerebrospinal fluid (CSF) evaluation, both for cytology and tumor markers, cannot be overstated. A significant proportion of childhood brain tumors tend to seed throughout the neuraxis by the CSF pathways. Thus, evaluation of CSF cytology prior to surgical perturbation of the primary tumor should be undertaken whenever safely feasible, in order to avoid the dilemma of postoperative positive CSF cytology and its questionable significance.