Platinum-iridium subdermal magnetic resonance imaging-compatible needle electrodes are suitable for intraoperative neurophysiological monitoring during image-guided surgery with high-field intraoperative magnetic resonance imaging: an experimental study.

Neurosurgery aims to achieve maximal tumor resection while preserving neurological function. Tools such as neuronavigation, high-field intraoperative magnetic resonance imaging (iMRI), and intraoperative neurophysiological monitoring (IOM) have consistently helped to achieve this goal, but integration has often been difficult. Surgery of eloquent areas requires IOM, which in an operating theater equipped with high-field (1.5-T) iMRI could present several issues. To identify the electrodes types more suitable for IOM in a high-field iMRI operating theater by performing an experimental study on phantoms, to report our experience with platinum-iridium (Pt/Ir) electrodes during surgery, and to prove that integration between IOM with Pt/Ir electrodes and high-field iMRI is safe and reliable. Electrodes of different materials (gold, Pt/Ir, and stainless steel) were tested on jelly phantom and apples to evaluate their safety and compatibility. Subsequently, electrodes were tested on 5 healthy volunteers before being used on patients. None of the different electrodes presented thermal instability, and no damage to the volunteers' skin occurred. Stainless steel electrodes caused severe imaging distortion. Gold electrodes had no distortion, but their high cost makes their use in routine surgery unaffordable. Pt/Ir electrodes are significantly less expensive than gold electrodes and were completely safe, compatible, and suitable for use in an operating theater with high-field iMRI, providing excellent IOM and mild interference that did not affect the quality of intraoperative imaging. We suggest the use of Pt/Ir electrodes for IOM in 1.5-T iMRI suites. DTI, diffusion tensor imagingiMRI, intraoperative magnetic resonance imagingIOM, intraoperative neurophysiological monitoring.