First-in-human spinal cord tumor imaging with fast adaptive focus tracking robotic-OCT

Abstract: Current surgical procedures for spinal cord tumors lack in vivo high-resolution, high-speed multifunctional imaging systems, posing challenges for precise tumor resection and intraoperative decision-making. This study introduces the Fast Adaptive Focus Tracking Robotic Optical Coherence Tomography (FACT-ROCT) system,designed to overcome these obstacles by providing real-time, artifact-free multifunctional imaging of spinal cord tumors during surgery. By integrating cross-scanning, adaptive focus tracking and robotics, the system addresses motion artifacts and resolution degradation from tissue movement, achieving wide-area, high-resolution imaging. We conducted intraoperative imaging on 21 patients, including 13 with spinal gliomas and 8 with other tumors. This study marks the first demonstration of OCT in situ imaging of human spinal cord tumors, providing micrometer-scale in vivo structural images and demonstrating FACT-ROCT's potential to differentiate various tumor types in real-time. Analysis of the attenuation coefficients of spinal gliomas revealed increased heterogeneity with higher malignancy grades. So, we proposed the standard deviation of the attenuation coefficient as a physical marker, achieving over 90% accuracy in distinguishing high- from low-grade gliomas intraoperatively at a threshold. FACT-ROCT even enabled extensive in vivo microvascular imaging of spinal cord tumors, covering 70 mm * 13 mm * 10 mm within 2 minutes. Quantitative vascular tortuosity comparisons confirmed greater tortuosity in higher-grade tumors. The ability to perform extensive vascular imaging and real-time tumor grading during surgery provides critical information for surgical strategy, such as minimizing intraoperative bleeding and optimizing tumor resection while preserving functional tissue.