New technique slashes diagnosis time during brain surgery

Neurosurgeons want the quickest, most accurate information to help them make decisions during brain tumour surgery. A new method could accelerate that process.

Neurosurgeons and pathologists at Michigan Medicine are the first to execute stimulated Raman histology (SRH), a method that improves speed and diagnostic efficiency, in an operating room.

The researchers imaged tissue from 101 neurosurgical patients using conventional methods and the new method. Both techniques produced accurate results, they found, but the new method was much faster.

SRH, if applied widely, could change the pace and structure of an operation.

‘By achieving excellent image quality in fresh tissues, we’re able to make a diagnosis during surgery,’ says first author Daniel A. Orringer, M.D., assistant professor of neurosurgery at the University of Michigan Medical School. ‘This eliminates the lengthy process of sending tissues out of the OR for processing and interpretation.’

Today’s workflow for determining a diagnosis during an operation requires the surgeon wait 30 to 40 minutes while tissue is sent to a pathology lab for processing, sectioning, staining, mounting and interpretation. The entire team in the operating room may be idle while waiting for pathology results, Orringer says.

‘Our technique may disrupt the intraoperative diagnosis process in a great way, reducing it from a 30-minute process to about three minutes,’ Orringer says. ‘Initially, we developed this technology as a means of helping surgeons detect microscopic tumour, but we found the technology was capable of much more than guiding surgery.’

Stimulated Raman scattering microscopy, the technology behind SRH, was developed in 2008, but the hazardous lasers involved made it unsuitable for use in an operating room. A clinical version has now been developed and tested in the operating room for more than a year at U-M, with the fibre-laser-based microscope mounted onto a clinical cart that plugs into the wall.

To interpret the samples, researchers developed SRH, which creates images similar to those currently in use.

SRH uses virtual colouring to highlight the cellular and architectural features of brain tumours, with a result resembling traditional staining. The pathologist is then able to differentiate the tumour tissue from normal brain as usual.

‘It’s very similar to what we currently do in our intraoperative diagnosis, with the exception that the tissue is fresh, has not been processed or stained,’ says senior author Sandra Camelo-Piragua, M.D., assistant professor of pathology at U-M.

In the Nature Biomedical Engineering study, neuropathologists were given 30 specimen samples processed by SRH or traditional methods. They were told the same information about each patient’s medical history and the location of the tumour and asked to make a diagnosis.

Those pathologists, the U-M researchers found, were equally likely to make a correct diagnosis, whether they used SRH or conventional slides.

‘SRH imaging will ensure that appropriate and good-quality tissue is collected to reach our ultimate goal: accurate diagnosis,’ Camelo-Piragua says.

University of Michigan