Table 1.

Intraoperative demarcation between tumor and normal brain tissue.

Methods	Suitability	Characteristics
Image-based navigation	Plan the surgical approach to biopsy the lesion; attempt gross tumor resection	Provides information of tumor size, shape, and location; not a true real-time toola
Intraoperative tissue sampling	Confirm tumor diagnosis; possibly identify tumor origin and grade	High-diagnostic value; specimens are piecemeal and discontinuous; must combine multiple specimens; often not real-time
Electrophysiological monitoring	Identify important functional regions and circuits; minimize neurologic deficits	Indirect tumor delineation via the responses or feedback of awake patients; real-time
Enhanced visual tumor demarcationb	Identify tumor remnants or infiltrating tumors to obtain complete resection	Strong correlation with the surgeon’s view of the field; real-time

^aMRI information for navigation is not real-time.

^bMicrospectrofluorometer is similar to the method of enhanced visual tumor demarcation by using a readout device to detect the fluorescence difference instead of visualization.