Over the past decade, a technique widely used by ophthalmologists to assess retinal blood flow, near-infrared ICG angiography, has been applied to neurosurgical patients undergoing a wide variety of cerebrovascular procedures. This technique offers the advantage of real-time visualization of cerebral blood flow through the operating microscope at the time the procedure is being performed. Indocyanine green is an ideal agent for imaging vessels as it is tightly bound to plasma albumin, has a short half-life, and maintains an acceptable safety profile. Furthermore, the excitation and emission profiles for ICG lie in the near-infrared wavelengths, which allow penetration and imaging of vessels below a few millimeters of tissue.
Patients with either an aneurysm, compressive syndromes or pituitary and intracranial tumor will be enrolled in the study. By taking advantage of the natural fluorescence of indocyanine green (ICG) within the red spectrum and applying a light filter to the endoscope eyepiece and camera it will show as to whether this technique provides adequate visual information to differentiate perfusion in tumor and surrounding structures and to evaluate normal vessels for aneurysm and compressive syndromes procedures.
