New imaging method enables rapid assessment of tumor tissue
"This technology reduces tissue processing time and could significantly increase the accuracy of brain tumor surgery in an operating room," said Behrouz Shabestari, Ph.D., director of the NIBIB program in Optical Imaging and Spectroscopy. "It basically optimizes the surgical result and has the potential to improve patient outcomes by increasing safety and survival rates."

The team from the University of Michigan Medical School, led by Daniel Orringer, M.D., a neurosurgeon and lead author of the paper, used stimulated Raman scattering (SRS), a type of microscopy that does not require tissue processing, or slicing the tissue and staining it. They adapted the procedures so they could be performed in the operating room. Previously, microscopes capable of SRS were too big and expensive for a clinical setting. But by switching to a fiber-laser microscope, which uses the same type of fiber optics as internet and phone cables, and devising a way to decrease background signals common to fiber-laser images, the team created a portable, safe, high-resolution system and validated its use in more than 100 patients.

They also created a way to quickly process the resulting images, called stimulated Raman histology (SRH). The new method takes advantage of intrinsic chemical properties of the tissue, making proteins and DNA appear purple and lipids appear pink. The resulting image is strikingly similar to the widely used hematoxylin and eosin (H&E) staining, so pathologists don't need to be specially trained to interpret it. By eliminating the time-consuming process of sectioning and staining, SRH takes about three minutes, 10 times less than standard techniques used during surgery. When tested on 30 samples, pathologists came to similar conclusions using SRH as when using conventional techniques.