gms | German Medical Science

Objective: Neuronavigation has up to now been of limited use in aneurysm surgery. Nevertheless, especially in case of small or atypical located aneurysms the use of neuronavigation might be beneficial. Typically, digital subtraction angiography (DSA) or computed tomography angiography data is used preoperatively for diagnostic purposes. Whereas 3D CTA data can be easily integrated in the neuronavigation set up, the co-registered integration of 2D DSA data is somehow up to now still limited. With a recent integration of 2D-3D image fusion for vascular data sets into common neuronavigation system, this approach could improve individual treatment strategies by analyzing already preoperatively complicated neuroanatomical relationships, aneurysm location, and orientation, followed by an intraoperative application of this knowledge.

Methods: Ten patients with confirmed intracranial aneurysms were analyzed. The preoperative CTA images were selected besides corresponding frontal and lateral preoperative DSA images. Using the Image Fusion Angio Element (Brainlab, Munich, Germany), various regions of interest for image fusion could be used (all vessels or limited to left / right carotid artery). The 3D CTA image was superimposed as a maximum intensity projection over the 2D DSA image and was manually adjusted in orientation and size followed by automated registration to allow for optimal registration accuracy, with as many adaptions and repetitions of the process as needed.

Results: 2D-3D image registration could be successfully performed in all cases. The mean time needed for fusion of the lateral and frontal projection data onto CTA data sets was 16.57 minutes ± 2.39 minutes [12.25 minutes; 20.33 minutes]. In all cases multiple adaptions of the registration process were needed. In combination with intraoperative patient registration this enabled navigation in projection data, especially useful in cases where the aneurysm might not be clearly seen in 3D CTA data.

Conclusion: Even though up to now moderate time consuming manual alignment and adaption is needed, successful co-registration of 2D-3D vascular data was performed enabling the integration of angiographic projection data into the neuronavigational setup. Even though the use in aneurysm surgery might be limited this could be of major interest in surgical treatment of vascular malformations, additionally enabling information about flow dynamics in the cranial planning procedure but also the intraoperative application.