Usually, conventional magnetic resonance spin echo images (MRI) are sufficient to establish the diagnosis of intracranial pathology. Planning and executing a neurosurgical procedure requires the ability of the neurosurgeon to transform these two-dimensional MRI into a three-dimensional (3-D) virtual image of the pathology and the surrounding neuronal anatomy. Such mentally performed transformations after sequential observation of the individual two-dimensional slices (i.e., MRI and angiography) may be virtual tasks that are very difficult or sometimes impossible to achieve. Using 3-D MRI data sets and a semiautomatic computer assisted segmentation technique, we tried to simulate intraoperative situs-based 3-D MRI reconstructions of parasagittal and parafalcine central region tumors. The MRI reconstructions were integrated into the neurosurgical planning procedure as an additional tool. They proved to be an important adjunct in determining the distinct anatomy of the intracranial pathology in its relation to the surrounding and overlying brain and vascular (especially venous) anatomy. With 10 patients with central region parasagittal and parafalcine tumors, we found that the 3-D MRI reconstructions revealed additional information compared to conventional cross-sectional images and had an influence on neurosurgical planning and strategy, improving neurosurgical performance and patient outcome.