[Photoelectric intraoperative diagnosis of brain tumors]

Intraoperative examination of 43 neuro-oncological patients was conducted. The exact boundaries of the tumors and their extension into tumorous cysts and the ventricles of the brain were determined by means of a puncture cannula fitted with a photoelectric transducer. Comparative analysis of the regional blood flow in the peripheral tissues, on the surface of the cerebral hemispheres, in the white and tumorous tissues along the length of the puncture canal was made by the method of surface and intratissue photoplethysmography. It was established that the optic properties of most tumors, cysts, and CSF spaces significantly differed from those of the white matter. Analysis of intratissue photoplethysmogram revealed considerable fluctuations of the pulsed blood flow in the white matter and tumorous tissue, reorganization of blood flow in the white matter and tumors was found in some cases counterphase to that on the surface of the cerebral hemispheres and in the peripheral tissues.