Advanced approach for intraoperative MRI guidance and potential benefit for neurosurgical applications

Purpose: To present an advanced approach for intraoperative image guidance in an open 0.5 T MRI and to evaluate its effectiveness for neurosurgical interventions by comparison with a dynamic scan-guided localization technique. Materials and Methods: The built-in scan guidance mode relied on successive interactive MPI scans. The additional advanced mode provided real-time navigation based on reformatted high-quality, intraoperatively acquired MR reference data, allowed multimodal image fusion, and used the successive scans of the built-in mode for quick verification of the position only. Analysis involved tumor resections and biopsies in either scan guidance (N = 36) or advanced mode (N = 59) by the same three neurosurgeons. Technical, surgical, and workflow aspects were compared. Results: The image quality and hand-eye coordination of the advanced approach were improved. While the average extent of resection, neurologic outcome after functional MRI (fMRI) integration, and diagnostic yield appeared to be slightly better under advanced guidance; particularly for the main surgeon, statistical analysis revealed no significant differences. Resection times were comparable, while biopsies took around 30 minutes longer. Conclusion: The presented approach is safe and provides more detailed images and higher navigation speed at the expense of actuality. The surgical outcome achieved with advanced guidance is (at least) as good as that obtained with dynamic scan guidance.