Image Fusion and 3D Roadmapping in Endovascular Surgery
Practitioners of endovascular surgery have historically utilized two-dimensional (2D) intraoperative fluoroscopic imaging, with intra-vascular contrast opacification, to treat complex three-dimensional (3D) pathology. Recently, major technical developments in intraoperative imaging have made image fusion techniques possible: the creation of a 3D patient-specific vascular roadmap based on preoperative imaging which aligns with intraoperative fluoroscopy, with many potential benefits. First, a 3D model is segmented from preoperative imaging, typically a CT scan. The model is then used to plan for the procedure, with placement of specific markers and storing of C-arm angles that will be used for intra-operative guidance. At the time of the procedure, an intraoperative cone-beam CT is performed and the 3D model is registered to the patient’s on-table anatomy. Finally, the system is used for live guidance where the 3D model is codisplayed overlying fluoroscopic images. There are many applications for image fusion in endovascular surgery. We have found it to be particularly useful for endovascular aneurysm repair (EVAR), complex EVAR, thoracic endovascular aneurysm repair (TEVAR), carotid stenting and for type 2 endoleaks. Image fusion has been shown in various settings to lead to decreased radiation dose, less iodinated contrast use and shorter procedure times. In the future, fusion models may be able to account for vessel deformation caused by the introduction of stiff wires and devices and the user-dependent steps may become more automated. In its current form, image fusion has already proven itself to be an essential component in the planning and success of complex endovascular procedures.