Intraoperative high-field MRI: anatomical and functional imaging.

Intraoperative high-field magnetic resonance (MR) imaging with integrated microscope-based navigation is at present one of the most sophisticated technical methods providing a reliable immediate intraoperative quality control. It enables intraoperative imaging at high quality that is up to the standard of up to date pre- and postoperative neuroradiological routine diagnostics. The major indications are pituitary tumor surgery and glioma surgery. In pituitary tumor surgery intraoperative MRI helps to localize hidden tumor remnants that would be otherwise overlooked. The same is true for glioma surgery, where the optimal extent of resection by simultaneous preservation of functional integrity can be achieved. This is possible since high-field MR imaging offers various modalities beyond standard anatomical imaging, such as MR spectroscopy, diffusion tensor imaging, and functional MR imaging which may also be applied intraoperatively, providing not only data on the extent of resection and localization of tumor remnants but also on metabolic changes, tumor invasion, and localization of functional eloquent cortical and deep-seated brain areas.