The value of intraoperative scans during CT-guided stereotactic procedures.

The accuracy stereotactic procedures performed during the pre-computed tomography (CT) era was confirmed by intraoperative X-ray pictures. With the availability of CT it is now possible to confirm the position of the probe-tip on an image of the target. For biopsy of small lesions in critical areas of the brain, permanent placement of radioactive seeds, or thalamotomy, it would be desirable to have confirmation of the site of the probe-tip prior to performing the main step of the procedure. Intraoperative CT was performed in 216 stereotactic procedures carried out on the scanner table including biopsies, aspiration of cysts, brachytherapy, aspiration of abscesses, thalamotomy, and evacuation of intracerebral hematoma. In 6 cases, inaccuracies were detected, which it was possible to correct so as to place the probe where desired.