[Intraoperative diagnosis of cerebral gliomas]

At the Burdenko Institute for Neurosurgery in Moscow, the following methods are used for the demarkation of cerebral gliomas: Beta-radiometry, rheometry = measurement of th electrical resistance of the cerebral tissue, staining of the tumour prior to the surgical intervention by means of a Serbinenko catheter, puncture biopsy as well as thermometry. The most frequently used techniques are beta-radiometry and rheometry. The methods are simple in application and the results are reliable. The accuracy of the localisation of a cerebral glioma by means of beta-radiometry is 98 per cent. For the impedance measurement a frequency of 1000 Hz is used. Liquids show the lowest and fibrous meningiomas the highest electrical resistance values. On an average the resistance of cerebral tumours is half as high as that of the average normal brain tissue. In almost all operations one tries to obtain an information about the extent and position of the glioma by means of brain puncture. A special needle probe has been designed to obtain tissue pieces for histological examinations. Experience has also been gained with ultrasonic probing and with temperature measurements of tumour and brain tissue. the interior of the tumours shows a 0.5 to 3 degrees C higher temperature.