Researchers have successfully integrated a megahertz-speed optical coherence tomography (MHz-OCT) system into a commercially available neurosurgical microscope, showcasing its clinical value in identifying tumor margins during brain surgery. OCT is a non-invasive imaging technique that provides high-resolution, cross-sectional images of tissue, with most commercial systems only able to acquire around 30 2D images per second. The MHz-OCT system developed in this study operates at speeds 20 times faster than conventional systems, enabling the creation of 3D images that penetrate below the brain’s surface and can identify hidden abnormalities needing treatment.
Published in Biomedical Optics Express by Robert Huber and his team, the study illustrated the utility of the microscope-integrated MHz-OCT system in acquiring high-quality volumetric images during surgery within seconds. These images offer valuable insights into brain anatomy, such as blood vessels located beneath the brain’s membrane, enhancing surgical precision and outcomes. The system’s rapid acquisition capabilities make it suitable for various neurosurgical procedures beyond brain tumor resections, providing detailed information on anatomical structures below the brain’s surface.
The researchers’ quest to accelerate OCT technology involved enhancing light sources and sensors, leading to the development of an MHz-OCT system capable of achieving over a million depth scans per second. This imaging speed is made possible by incorporating a Fourier domain mode locking laser, which was initially conceptualized by Huber during his doctoral research at MIT. The evolution of GPU technology over the past 15 years has further facilitated the processing of raw OCT signals into meaningful visuals without the need for bulky computational resources.
Validating the system for use in neurosurgery, the researchers integrated the MHz-OCT instrument with a specialized microscope commonly used by surgeons for improved brain visualization. After passing calibration and tissue phantom tests, the system underwent patient safety evaluations before embarking on a clinical study involving 30 brain tumor resection surgeries. Despite initial modest expectations due to its retrofit nature, the system delivered exceptional image quality, exceeding the researchers’ projections.
Through the clinical study, the researchers gathered a substantial amount of OCT imaging data alongside corresponding histological information. While they are still in the early stages of interpreting this data and developing AI tools for tissue classification, the potential for widespread adoption of this technology in brain tumor resection neurosurgery remains years away. Future research will explore the system’s efficacy in pinpointing brain activity during surgery, offering promise for enhancing the precision of neuroprosthetic electrode implantation and enabling more accurate control of prosthetic devices by tapping into the brain’s electrical signals.
