Cortical vessel imaging and visualization for image guided depth electrode insertion.

To avoid intracranial hemorrhage during minimally invasive depth electrode insertion without craniotomy for epilepsy surgery, precise in vivo imaging of cortical vessel and relevant rendering methods are critical, and should be used in preoperative planning. In this study, a non-invasive phase contrast MR angiography (PC-MRA) method was chosen for cortical vessel imaging. After image pre-processing (registration and segmentation), three visualization methods were implemented to optimize the vessel imaging and brain tissue rendering for surgical planning. The processed results were evaluated by comparing with intraoperative photographs. The results showed occurrences of missing vessels between imaging and photos (18.3%, 6 cases), but these could be compensated by realistic sulci visualization methods. The results showed 3D texture mapping to be the most suitable cortex visualization method for use in surgical navigation. Based on the methods and evaluations, a new surgical planning system and criteria of usage were developed with input from the surgeons' experience using the prototype system. This system could greatly help reduce the risk of the intracranial hemorrhage during electrode insertion and also avoid potential risks caused by contrast agent injections for contrast enhanced MRA or CTA.