A Dedicated Tool for Presurgical Mapping of Brain Tumors and Mixed-Reality Navigation During Neurosurgery

Abstract

Brain tumor surgery requires a delicate tradeoff between complete removal of neoplastic tissue while minimizing loss of brain function. Functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) have emerged as valuable tools for non-invasive assessment of human brain function and are now used to determine brain regions that should be spared to prevent functional impairment after surgery. However, image analysis requires different software packages, mainly developed for research purposes and often difficult to use in a clinical setting, preventing large-scale diffusion of presurgical mapping. We developed a specialized software able to implement an automatic analysis of multimodal MRI presurgical mapping in a single application and to transfer the results to the neuronavigator. Moreover, the imaging results are integrated in a commercially available wearable device using an optimized mixed-reality approach, automatically anchoring 3-dimensional holograms obtained from MRI with the physical head of the patient. This will allow the surgeon to virtually explore deeper tissue layers highlighting critical brain structures that need to be preserved, while retaining the natural oculo-manual coordination. The enhanced ergonomics of this procedure will significantly improve accuracy and safety of the surgery, with large expected benefits for health care systems and related industrial investors.

Keywords: Brain tumors; MRI; Medical image; Mixed reality; Neurosugery.

Fig. 1

An example of a tumor hologram derived from MRI data and visualized in the HoloLens together with the “real world” scalp, after the anchorage procedure. The mixed-reality approach allows an immediate and clear understanding of the tumor position underneath the skull, helping the surgeon to delineate the best area for craniotomy

Fig. 2

Example of fMRI activation map of the hand motor areas (red-yellow) superimposed on the structural scan (gray) of a patient with a brain tumor, as calculated by our platform

Fig. 3

Example of the results obtained from the DTI module of our platform, showing the corticospinal tract

Fig. 4

Schematic representation of our prototype analysis platform and mixed-reality application

Fig. 5

Example of the volume viewer implemented in our mixed-reality application. While the surgeon is looking at the head through the HoloLens, he can activate a reslicing option using mid-air gestures allowing to visualize internal sections obtained from volumetric structural (here in gray) and functional/DTI (here in color) data

Fig. 6

The 3D-printed head phantom obtained from a structural MRI dataset, used to develop the anchorage procedure