Polarized light helps to perform neurosurgical operations more accurately

Deep brain stimulation (DBS) is an effective treatment method for neurological disorders such as Parkinson’s disease, essential tremor, and obsessive—compulsive disorder. It is based on the precise installation of electrodes in certain areas of the brain to regulate pathological activity. But achieving millimeter accuracy is not an easy task: conventional imaging techniques, such as MRI, do not always make it possible to clearly distinguish between small and deep brain structures.

The new solution is polarized light optical tomography (PS-OCT). It works on the principle of reflecting light from different types of fabrics. If an MRI scan gives a picture with a resolution of millimeters, then PS-OCT shows the structure of the brain at the micron level — that is, ten times more detailed.

In a recent study, scientists tested this technology on an animal’s brain sample. They simulated a surgical operation: they inserted a thin probe into the brain and slowly began to pull it back, taking pictures. These images were compared with MRI scans and anatomical diagrams.

The results were promising. PS-OCT:

• It clearly showed me where the gray matter was and where the white matter was;
• revealed important fibers in the brain that cannot be seen on an MRI scan;
• It allowed us to build more accurate “brain maps” — this is important for choosing the location of the electrode.

The scientists emphasize that the technology so far shows the direction of the fibers only in two dimensions, but in the future full-fledged 3D visualization is possible. In addition, the probe used in the experiment is slightly thicker than standard electrodes, but there are already suitable thinner analogues.

According to one of the authors, Shadi Masumi, the technology can become a reliable assistant to a neurosurgeon: “It provides high accuracy and shows important structures that were previously almost invisible. This will help surgeons perform operations even more accurately and safely.”

The next step is to test the method in real operations and compare it with other modern methods of studying the brain. If everything goes well, PS-OCT can improve the quality of life of thousands of patients.