ADVANCES IN BRAIN-TUMOR IMAGING

Scientists have taken advantage of the powerful imaging capability of computed tomographic and magnetic resonance (MR) scanners to analyze b rain tumor morphology in vivo. Recently, the development of functional MR imaging techniques have added the ability to noninvasively examine brain tumor function and physiology with near real-time temporal reso lution, and spatial resolution approaching that of anatomic images. Th is advance allows the study of cerebral blood volume, cerebral blood f low, and stimulated cortical activity, which have traditionally been w ithin the domain of positron emission tomography (PET) research. PET r esearch on brain tumors continues mainly with research into glycolytic rates and comparison with proton MR spectroscopic lactate data. These comparisons are facilitated by the refinement of two-dimensional MR s pectroscopic techniques, which provide comparable spatial resolution t o that of PET. On a more clinical note, several prospective studies in volving the MR contrast agent gadolinium have been carried out, specif ically those optimizing the timing of contrast-enhanced postoperative MR scans after resection of glioblastomas, using triple-dose contrast to increase sensitivity to brain metastases, and using contrast-enhanc ed MR imaging to study the efficacy of embolization in meningiomas.