Direct real-time intra-operative imaging of human brain tumor vessels using intravital microscopy

Our results show that HIVM can be used to study the anatomy and blood flow dynamics of the microvasculature of both non-infiltrated and infiltrated brain tissues intra-operatively in real-time, in patients with diverse pathologies ranging from non-cancerous and cancerous primary brain tumors to intracranial metastatic malignancies. Our experience shows that HIVM can detect areas of BBB integrity in glioblastomas, with clear flow through functioning vessels without noticeable leakage into the parenchyma, as well as areas of clear BBB disruption and leakage, in a direct demonstration of what was previously reported from MRI and PET studies. Further, in line with our prior reports in other cancer types, we demonstrate that a significant proportion of tumor vessels are non-functioning particularly in the most aggressive type of gliomas, glioblastomas. Interestingly, our series showed only functional vessels in the oligodendroglioma case, highlighting its different biological background and the need for further studies into its unique development. Collectively, this study is important for the brain tumor field as it demonstrates the feasibility of using HIVM in the operating room during brain tumor surgeries to assess real-time BBB integrity and vessel anatomical and dynamic assessment, which will enable future studies aimed at demonstrating the efficacy and feasibility of BBB opening with enabling technologies.