3-Tesla intraoperative MR imaging for neurosurgery.

Intraoperative magnetic resonance (MR) image-guided neurosurgery has been performed since 1994. Using a 1.5-Tesla (T) intraoperative MR imaging system, we have performed more than 750 interventional procedures. Having validated the safety and efficacy of this surgical technique that is relatively amenable to nearly all new in-hospital MR suites, we sought to adapt this approach at our sister hospital where a new short-bore 3-T MR suite was being installed. Using many of the lessons learned from our initial experience at 1.5-T, we designed a new interventional suite that would enable surgery to be performed entirely within a 3-T MR environment. All surgical instrumentation including electrocautery, fiberoptic headlamp, power drill, and ultrasonic aspirator was entirely MR-compatible. A few items with limited ferromagnetism were utilized within the magnetic field under strict precaution. From 2/04 to 7/05, those cases initially performed within the 3-T surgical suite included one drainage and reservoir placement for a cystic craniopharyngioma, five brain biopsies and two craniotomies; one for open brain biopsy and another for lesion resection. The craniopharyngioma was successfully aspirated and had the reservoir catheter placed within the cyst. All five brain biopsies yielded diagnostic tissue. The craniotomy for mass resection demonstrated radiation necrosis. Although the metallic artifact from the biopsy needle was more prominent than at 1.5-T, accurate image interpretation was possible. Surgical needles, disposable scalpel, disposable razor, and surgical stapler were minimally ferromagnetic and safely controlled by the surgeon. There were no adverse events associated with any procedure. MR-guided neurosurgery can be safely and effectively performed at 3-T. The surgical environment at 3-T is comparable to that present at 1.5-T.