[Localization of small subcortical processes in important functional zones by preoperative x-ray computed tomography].

Operative approach the subcortical lesions in a functionally important region must be small, sure and sparing, thus requiring an exact preoperative localization. This is possible by using a little ringshaped cooperwire, which does not produce artefacts on computerized tomographs and, by measuring distances between this cooperwire and the focal lesion.