ENHANCED OPTICAL IMAGING OF HUMAN GLIOMAS AND TUMOR MARGINS

ONE OF THE potential variables affecting the overall survival and qual ity of life of patients with intracranial gliomas is the extent of tum or resection that results in the smallest volume of residual disease. A technique involving enhanced optical imaging of human gliomas has th e potential to localize tumors, identify tumor remaining at the resect ion margins, and determine the grade of the tumor. In a preliminary st udy involving nine patients undergoing surgery for the removal of intr insic brain tumors, enhanced optical imaging was performed using indoc yanine green as an intravenous contrast-enhancement agent. Optical ima ges were obtained before and after injection of the indocyanine green. The studies in the nine patients showed differences in the dynamic op tical signals among normal brain, low-grade astrocytomas, and malignan t astrocytomas. Optical imaging of the resection margins in malignant tumors showed differences between adjacent normal tissue and remaining tumor tissue. Enhanced optical imaging of human gliomas using a contr ast-enhancing dye, indocyanine green, provides a potential means to di fferentiate between normal brain and tumor tissue at the cortical surf ace and in the depths of the resection margins. Having the ability to obtain real-time information and feedback in the operating room may al low neurosurgeons to maximize the extent of tumor resection while spar ing normal brain and increasing the diagnostic accuracy of intraoperat ive biopsies. Enhanced optical imaging potentially could facilitate th e accuracy and safety of surgery when tumors are removed at sites even outside the central nervous system.