Every second counts when a patient’s skull is open in the operating room. A new technique based on deep learning can shorten some brain surgeries.

What’s new: During brain cancer operations, surgeons must stop in mid-operation for up to a half hour while a pathologist analyzes the tumor tissue. Led by neurosurgeon Todd Hollon, researchers at the University of Michigan and elsewhere developed a test powered by deep learning that diagnoses tumor samples in only a few minutes. (The paper is behind a paywall.)

Key insight: The authors trained a convolutional neural network (CNN) to diagnose tumor samples based on a rapid digital imaging technique known as stimulated Raman histology (SRH).

How it works: Previous approaches require transporting tumor tissue to a lab, running assays, and analyzing the results. The new test takes place within the operating room: A Raman spectroscope produces two SRH images that measure different properties of the sample, and a CNN classifies the images.

  • The researchers fine-tuned the pretrained inception-resnet-v2 architecture on images from 415 patients. They trained the network to recognize 13 cancer types that account for around 90 percent of observed brain tumors.
  • A preprocessing algorithm derives from each image a set of overlapping, high-resolution patches. This procedure creates a uniform, CNN-friendly image size; boosts the number of training samples; and eases parallel processing.
  • The CNN predicts the tumor type of each patch, and the model chooses the diagnosis predicted most frequently in the patches.

Results: The researchers measured the CNN’s performance in a clinical trial (the first trial of a deep learning application in the operating room, they said). They evaluated tumor samples using the CNN as well as chemical tests and compared the results with clinical diagnoses. The CNN was 94.6 percent accurate, 0.7 percent better than the next-best method.

Why it matters: Chemical tests not only incur the risk of interrupting surgery, they also need to be interpreted by a pathologist who may not be readily available. The CNN renders a diagnosis directly, potentially increasing the number of facilities where such operations can be performed.

We’re thinking: Deep learning isn’t brain surgery. But brain surgery eventually might be deep learning.


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