In a major development in how tumors are excised, researchers at the University of Michigan have shown that it's possible to accurately analyze brain tumor tissue within the operating room and assess its nature using artificial intelligence. Tumor tissues typically look just like the healthy stuff around them. When a tumor is removed, parts that are near the edges (margins) are sent to the pathology lab for review. After staining and observations using a microscope, the pathologist can let the surgical team know whether it removed all of the tumor or left some behind. This takes a long time, so much so that typically a follow-up surgery is required if the margins are not completely excised.