NIMG-12. MULTICOLOURED-ASSISTED SURGERY FOR RESECTION OF HIGH GRADE GLIOMAS WITH 5-AMINOLEVULINACID

Abstract INTRODUCTION Fluorescence guided surgery with the use of 5-aminolevulinacid (5 -ALA) is nowadays the state of the art treatment of high grade gliomas. However, intraoperative visualization of 5-ALA under dark blue light remains challenging, especially when leaking blood covers parts of the surgical field, where tumor fluorescence becomes invisible. To overcome this problem and combine the brightness of visible light with the information delivered by fluorescence we developed multispectral fluorescence, a technique able to project both information in real time to the surgeon’s eyes, and embedded it on a surgical microscope. METHODS We examined 40 patients with brain tumors who underwent surgery, using the MFL operative technique. The tumors involved comprised of 20 glioblastomas, 7 astrocytomas WHO III, 5 meningiomas and 8 metastatic tumors. The MFL technique with the real-time overlay of 5-ALA fluorescence and white light was intraoperatively compared to the classic blue filter detecting 5-ALA fluorescence. RESULTS The tumor was in all cases clearly visible and highlighted from the surrounding tissues. The pseudocolor we chose to visualize the tumor was green, representing 5-ALA fluorescence, with the surrounding brain tissueremained in its origin white color. In the cases where blood was covering the surgical field, orientation was easy to maintain, due to the additional information delivered from the white light image. CONCLUSIONS The MFL technique embedded on a surgical microscope opens the way for a precise and clear visualization of tumor 5-ALA fluorescence in real time under white light. It can be easily implemented in the resection of all tumors accumulating 5-ALA. Drawbacks of classic 5-ALA fluorescence such as hidden fluorescence because of overlying blood could be overcome with the presence of additional white light and the clear visualization of the exposed brain.