Application of intraoperative indocyanine green videoangiography to brain tumor surgery

Background Videoangiography using indocyanine green (ICG) has been used in the ophthalmologic field for a long time. It was introduced to the neurosurgical field several years ago but has been limited to vascular surgeries. We applied ICG videoangiography to brain tumor surgery and evaluated the usefulness. Methods Twenty-three patients with a brain tumor who underwent microsurgical resection were analyzed. The pathological diagnosis was meningioma in 15 patients, metastasis in three, glioma in three, and hemangioblastoma in two. A microscope with a special filter and infrared excitation light to illuminate the operating field was used in this study. The intravascular fluorescence was imaged with a video camera attached to the microscope. ICG was injected intravenously with the dose of 5-25 mg, and overall, ICG was injected intraoperatively 32 times. Results ICG videoangiography allowed for an excellent evaluation of blood flow in the tumoral and peri-tumoral vessels both before and after the resection in all cases. Conclusions ICG videoangiography is a useful method for monitoring blood flow in the exposed vessels during microsurgery for a brain tumor. This noninvasive method is simple, safe, cost-effective, and easily repeatable. Before resection, it provides information on the tumoral and peri-tumoral circulation including sequential visualization of vessels or direction of the blood flow. After resection, it checks the patency of the peri-tumoral vessels and is especially useful for the vein. This ICG videoangiography can be an alternative tool to intraoperative angiography or Doppler ultrasonography in selective cases.