From intraoperative patient transport to surgery in the fringe field - Intraoperative application of magnetic resonance imaging using a 0.2-Tesla scanner: The erlangen experience

摘要

Intraoperative low-field magnetic resonance imaging (iMRI) was performed using a 0.2-tesla scanner located in a radiofrequency-shielded operating room. As designated in the initial concept of a twin operating room, surgery was performed in an adjacent operating room with use of intraoperative patient transport (n = 166). The introduction of nearly magnetic resonance-compatible navigation microscopes, which can be used in the fringe field of the scanner, obviated the need for cumbersome, long-distance intraoperative patient transportation by performance of surgery on the extended table of the scanner at the 5-gauss line (n = 164). In lesions adjacent to eloquent brain areas, microscope- and pointer-based neuronavigation with integrated functional data from either magnetoencephalography or functional MRI was applied. Since 1996, a total of 330 patients were investigated. No adverse effects due to iMRI were observed. Image quality was sufficient to evaluate the extent of tumor resection in the majority ofcases. The main indications for intraoperative MRI were evaluation of the extent of a resection in glioma, ventricular tumor, and pituitary tumor and use in epilepsy surgery. The effects of brain shift, which can compromise neuronavigation accuracy, could be compensated for by updating the neuronavigation system with iMRI data. Intraoperative MRI offers the possibility of further tumor removal during the same surgical procedure in case of tumor remnants, which increases the rate of complete tumor removal. Integrated use of functional neuronavigation in identifying eloquent brain areas prevents additional neurologic deficits.