Magnetic source imaging of the sensory cortex on the surface anatomy MR scanning

Surgery for lesions either within or close to the central sulcus of the brain always carries the risk of inducing iatrogenic motor or sensory deficits. We performed advanced magnetic source imaging (MSI) of the somatosensory cortex combined with 3-dimensional (3-D) surface anatomy scanning (SAS) of magnetic resonance imaging on 9 patients who had peri-Rolandic lesions, including 7 tumor cases, 1 arteriovenous malformation and 1 focal cortical dysplasia. 3-D MSI mapped out the entire somatosensory homunculus and localized the lesion on a cortical surface image. The results were then used for developing an appropriate surgical strategy and also as a reference in the operating room. This relationship and deduced localization were both confirmed by a cortical recording of the somatosensory evoked potentials at the time of surgery. Case histories of selected patients are briefly reported to demonstrate how the method can be used to improve the safety of surgical excisions of peri-Rolandic lesions. MSI on SAS including the cortical veins, was thus found to provide a readily interpretable presurgical road map of the cortical surface which compares favorably to that of intraoperative brain mapping.