Safety, efficacy, and functionality of high-field strength interventional magnetic resonance imaging for neurosurgery

OBJECTIVE: Interventional magnetic resonance imaging (MRI) allows neurosurg eons to interactively perform surgery using MRI guidance. High-field streng th (1.5-T) imaging permits exceptional observation of intracranial and spin al pathological features. The development of this technology and its applic ation to a variety of neurosurgical procedures are described. METHODS: We report on the first 101 cases that were treated in the interven tional MRI unit (between January 1997 and September 1998). These cases incl uded 39 brain biopsies, 30 tumor resections, 9 functional neurosurgical cas es, 8 cyst drainages, 5 laminectomies, and 10 miscellaneous cases. Patients ranged in age from 14 months to 84 years (median, 43 yr); 61 patients were male and 40 were female. Intraoperative functional techniques that were us ed to influence surgical decision-making included magnetic resonance spectr oscopy, functional MRI, magnetic resonance angiography and venography, chem ical shift imaging, and diffusion-weighted imaging. All surgery was perform ed using MRI-compatible instruments within the 5-gauss line and conventiona l instruments outside that line. RESULTS: All 39 brain biopsies yielded diagnostic tissue. Of the 30 tumor r esections, 24 (80%) were considered radiographically complete. The incidenc e of serious complications was low and was comparable to that associated wi th conventional operating rooms. One patient developed a Propionibacterium acnes brain abscess 6 weeks after surgery and another patient experienced S taphylococcus aureus scalp cellulitis after a brain biopsy, yielding an inf ection rate of less than 2%. No clinically significant hemorrhage was obser ved in immediate postoperative imaging scans, although one patient develope d a delayed hematoma after a thalamotomy. One patient experienced a stroke after resection of a hippocampal tumor. No untoward events were associated with MRI-compatible instrumentation or intraoperative patient monitoring. CONCLUSION: High-field (1.5-T) interventional MRI is a safe and effective t echnology for assisting neurosurgeons in achieving the goals of surgery. Pr eliminary results suggest that the functional capabilities of this technolo gy can yield data that can significantly influence intraoperative neurosurg ical decision-making. The rates of serious complications, such as infection , associated with this new technology were low.