Brain biopsy sampling by using prospective stereotaxis and a trajectory guide

Object. The authors describe their initial results obtained using a skull-m ounted trajectory guide for intraoperative magnetic resonance (MR) imaging- guided brain biopsy sampling. The device was used in conjunction with a new methodology known as prospective stereotaxis for surgical trajectory align ment. Methods. Between January 1999 and March 2000, 38 patients underwent 40 brai n biopsy procedures in which prospective stereotaxis was performed with the trajectory guide in a short-bore 1.5-tesla MR imager. In most cases, ortho gonal T-2-weighted half-Fourier acquisition single-shot turbo spin-echo (HA STE) images were used to determine the desired trajectory and align the dev ice. The surgical trajectory was defined as a line connecting three points: the target, pivot, and alignment stem points. In all cases, surgical speci mens were submitted for frozen section and pathological examination. Postop erative turbofluid-attenuated inversion-recovery and gradient-echo images w ere obtained to exclude the presence of hemorrhage. Trajectory determinatio n and alignment was simple and efficient, requiring less than 5 minutes. Co nfirmatory HASTE images were obtained along the biopsy needle as it was bei ng advanced or after reaching the target. All biopsy procedures yielded dia gnostic tissue. One patient with a lesion near the motor strip experienced a transient hemipansis of the hand related to passage of the biopsy needle, and another sustained a fatal postoperative myocardial infarction. No pati ent suffered a clinically significant or radiologically visible hemorrhage. Conclusions. In combination with prospective sterrotaxis, the trajectory gu ide provided a safe and accurate way to perform brain biopsy procedures.