CT-guided stereotactic biopsies using a modified frame and Gildenberg techniques.

Eighteen patients underwent CT guided stereotactic biopsies using either a Riechert-Mundinger stereotactic frame modified for use in the CT scanner or the CT-based intracranial landmark technique of Gildenberg and a Todd-Wells frame. In seven patients undergoing biopsy with the modified frame technique, representative tissue samples were obtained in all cases. Eleven patients had biopsies using the Gildenberg technique and representative tissue samples were obtained in 10 of the 11. No major postoperative complications occurred in either group. Both techniques allowed samples of intracranial tissue to be obtained safely and efficiently. The modified frame technique provided a higher degree of accuracy while the Gildenberg technique required significantly less CT time and provided a satisfactory degree of accuracy. In seven patients with ring enhancing lesions, biopsies of the enhancing rim provided diagnostic tissue while biopsy of the central low density center of the lesion in three patients provided necrotic material which was useful in histologically grading the tumour.