INTEGRATED IMAGING-SYSTEM FOR STEREOTAXIC NEUROSURGERY

Talairach's method remains the most universal of all stereotactic meth ods. It makes it possible to go back to an examination left interrupte d, but above all, it provides multiple lateral and coronal approaches in matters of epilepsy, radio-isotopes or photobiology. The advances a chieved in modem imaging methods, notably CT and MRI, and the performa nce of modem computers have enabled us to devise an integrated imaging system meant to accelerate and make feasible calculations of penetrat ing trajectories, according to the position of the target as previousl y defined by CT and MRI sections, and taking into account the position of vessels given by angiography. The principal options we selected we re : transfer onto video tapes of teleangiographic films and introduct ion of CT and MRI images obtained either from films or directly in dig its on cartridges or networks. The system includes an advanced PC-type microcomputer with 8 memories of 1 024/1 024 images : 4 mega octets r andom access memories and a hard disc of 150 mega octets ; 2 high-reso lution screens to present the images, dialogue tools (alphanumeric scr een, keyboard, trackball) and the usual peripherals. Our system perfor ms three main functions: it acquires images to create or complete the patient's records; it exploits the images by calculating the parameter s required for operations; it handles the records through the various peripherals of the system. Our system can retrace the proportional 3D squaring according to the CA-CP distance calculated from ventriculogra phy or MRI, and calculates the position of the SEEG electrodes. The st ereoscopic effect is obtained by means of glasses with liquid crystal obturator from two angiographic series: one orthogonal, the other 6-de grees out of phase. The daily use of this system on more thant 50 pati ents has shown that it is accurate and reliable, irrespective of the m akes of CT and MRI machines.