Gliomas are widely infiltrative tumors. Although an oncological resection is not feasible, there is compelling evidence that patients benefit from resection of the tumor. The surgical target is the main tumor bulk, which is defined as the contrast enhancing part of the tumor on preoperative MRI. Surgical treatment in gliomas is based on maximal safe resection of this mass. Several new technologies have been devised to maximize the resection and intraoperative MRI is one of these new technologies. Intraoperative MRI has been shown by many studies to increase the extent of resection in glioma surgery. Intraoperative determination of the extent of resection, however, requires use of intravenous contrast administration, which has some technical limitations. Fundamental problems associated with the use of contrast material are the enhancement at the resection margin and contrast leakage into the resection cavity. Both problems can complicate the differential diagnosis between residual tumor and surgically induced changes. Nowadays, the basic theory of a largest removal the tumor is the imaging boundary.
Knowledge of the spatial extent of gliomas is an essential prerequisite for the treatment planning. In particular, the localization of the border zone between tumor infiltrated and normal brain tissue is one of the major problems to be solved before beginning therapy. However, it is a well known problem that, in conventional magnetic resonance imaging (MRI), it often is difficult to detect areas with low tumor infiltration, especially in gliomas, because of their infiltrative and often diffuse nature.
