[New diagnostic imaging methods in neurosurgery: advent of anatomical and functional neuroimaging]

Progress in imaging techniques has contributed to improvements in reliable diagnosis and surgical decision making in neurosurgery. From the viewpoint of neurosurgeons, there are two major needs in the development of imaging techniques. One is greater accuracy in demonstrating the anatomy of the brain at microscopic resolutions and the other is visualization of function or metabolism that is invisible on surgical views. Use of 3.0 T magnetic resonance imaging (MRI) in clinical patients has revealed anatomy appropriate for microsurgery at high resolution, and three-dimensional reconstruction of MRI on high-specification computers helps neurosurgeons to understand the anatomy of the brain in individual patients. Functional imaging methods such as functional MRI, positron emission tomography, and magnetoencephalography have provided new insights in brain surgery, visualizing various cerebral functions on anatomic images. Recently, diffusion tensor imaging is used to visualize neural tracts passing through subcortical white matter and MR spectroscopy is used to show the metabolic status of lesions. These tools are also forms of functional imaging. New noninvasive imaging techniques are still being developed to visualize function more easily. Here, we summarize the roles of recent imaging techniques in our previous studies and discuss the future of imaging in neurosurgery.