Integrated imaging system for stereotactic neurosurgery

Talairach's method remains the most universal of all stereotactic methods. It makes it possible to go back to an examination left interrupted, but above all, it provides multiple lateral and coronal approaches in matters of epilepsy, radio-isotopes or photobiology. The advances achieved in modern imaging methods, notably CT and MRI, and the performance of modern computers have enabled us to devise an integrated imaging system meant to accelerate and make feasible calculations of penetrating trajectories, according to the position of the target as previously defined by CT and MRI sections, and taking into account the position of vessels given by angiography. The principal options we selected were: transfer onto video tapes of teleangiographic films and introduction of CT and MRI images obtained either from films or directly in digits on cartridges or networks. The system includes an advanced PC-type microcomputer with 8 memories of 1,024/1,024 images: 4 mega octets random access memories and a hard disc of 150 mega octets; 2 high-resolution screens to present the images, dialogue tools (alphanumeric screen, keyboard, trackball) and the usual peripherals. Our system performs three main functions: it acquires images to create or complete the patient's records; it exploits the images by calculating the parameters 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 ventriculography or MRI, and calculates the position of the SEEG electrodes. The stereoscopic effect is obtained by means of glasses with liquid crystal obturator from two angiographic series: one orthogonal, the other 6 degrees out of phase. The daily use of this system on more than 50 patients has shown that it is accurate and reliable, irrespective of the makes of CT and MRI machines.