Brain tumor surgery with the Toronto open magnetic resonance imaging system: Preliminary results for 36 patients and analysis of advantages, disadvantages, and future prospects

OBJECTIVE: Frameless navigation systems represent a huge step forward in th e surgical treatment of intracranial pathological conditions but lack the a bility to provide real-time imaging feedback for assessment of postoperativ e results, such as catheter positions and the extent of tumor resections. A n open magnetic resonance imaging system for intracranial surgery was devel oped in Toronto, by a multidisciplinary team, to provide real-time intraope rative imaging. METHODS: The preliminary experience with a 0.2-T, vertical-gap, magnetic re sonance imaging system for intraoperative imaging, which was developed at t he University of Toronto for the surgical treatment of patients with intrac ranial lesions, is described. The system is known as the image-guided minim ally invasive therapy unit. RESULTS: Between February 1998 and March 1999, 36 procedures were performed , including 21 tumor resections, 12 biopsies, 1 transsphenoidal endoscopic resection, and 2 catheter placements for Ommaya reservoirs. Three complicat ions were observed. All biopsies were successful, and the surgical goals we re achieved for all resections. Problems included restricted access resulti ng from the confines of the magnet and the imaging coil design, difficultie s in working in an operating room that is less spacious and familiar, incon sistent image quality, and a lack of nonmagnetic tools that are as effectiv e as standard neurosurgical tools. Advantages included real-time imaging to facilitate surgical planning, to confirm entry into lesions, and to assess the extent of resection and intraoperative and immediate postoperative ima ging to confirm the extent of resections, catheter placement, and the absen ce of postoperative complications. CONCLUSION: Intraoperative magnetic resonance imaging has great potential a s an aid for intracranial surgery, but a number of logistic problems requir e resolution.