[Tomodensitometry in stereotaxic conditions (possibilities and limitations in the diagnosis and treatment of brain lesions)].

The stereotaxic approach of cerebral lesions for diagnostic (biopsies) and/or therapeutic purposes (interstitial radiotherapy) has been well documented. These techniques depend on an exact spatial definition of the tumoral volume, which is often difficult to obtain through conventional neuroradiology, stereoencephalography, rheography... The use of tomodensitometry in this context is obviously of upmost interest if, and only if, the scan itself is obtained in stereotaxic conditions. The authors present a stereotaxic system with which all the diagnostic data, including CT scan itself, are recorded and matched within the same stereotaxic space. This method achieves an exact mapping of lesions within the actual stereotaxic brain space. Hence any further stereotaxic gesture can be calculated and controlled with a suitable accuracy. The interest of these procedures in the management of brain lesions is demonstrated through an experience of 52 supra tentorial tumors. 13 cases of lesions under 20 mm in diameter are especially discussed.