AN INTRACEREBRAL SONOGRAPHIC CATHETER AS AN ADJUNCT TO STEREOTAXIC GUIDED ENDOSCOPIC PROCEDURES

To facilitate stereotactic biopsies of intracerebral tumor lesions, to obtain important additional diagnostic information during the procedu re and to precisely guide biopsy instrumentation devices to spots of i nterest, catheter sonography was combined with intracerebral endoscopy intraoperatively in two patients. All catheter instrumentation was pe rformed through the stereotactic puncture channels, A 30 Megahertz ult rasound transducer mounted on the tip of a flexible 5 French catheter is sufficiently penetrating surrounding brain tissue, resulting in hig h resolution images at a maximum radial penetration depth of 15 mm. No rmal brain tissue could be differed from intracerebral tumor tissue in both patients. Smaller tumor lesions within the close surrounding of a solid intracerebral tu mor mass clearly appeared in ultrasound. Sinc e diagnostic endoscopy in stereotactic procedures is limited to the su rface of a puncture channel, intracerebral ultrasound adds important i nformation about the underlying type of tissue, We found that the comb ination of both methods facilitates guiding of biopsy instrumentation devices to the spots of interest in stereotactic procedures. In both e xamined patients all biopsy samples were histologically identified as intracerebral lymphoma. Since ultrasound clearly identified intracereb ral blood vessels as tubular hyporeflective structures, the risk of bi opsy related hemorrhage could be diminished.