IVUS-Based Local Vessel Estimation for Robotic Intravascular Navigation

Intra-operative local 3D vessel representations have the potential to significantly decrease the use of contrast agents and exposure to ionizing radiation during endovascular procedures, while overcoming the 2D visualization limitation of fluoroscopic guidance. By fusing intravascular ultrasound (IVUS) imaging and electromagnetic (EM) pose sensing in a robotic catheter tip, a real-time local 3D model of the vasculature could be constructed intra-operatively. This letter proposes the use of a cylinder model to approximate the vessel geometry near the catheter tip. An unscented Kalman filter is employed to robustly estimate the cylinder that best fits IVUS and EM data while navigating through the vessel. This forms a radiation-free alternative to conventional radiation-based guidance. Validation on one in silico and two in vitro models showed median estimation errors of cylinder radius of 0.14 mm, 0.42 mm and 0.70 mm; cylinder position of 0.45 mm, 1.07 mm and 0.96 mm; and cylinder orientation of 2.94 degrees, 4.60 degrees and 3.03 degrees showing great potential for helping interventionists preventing harmful interactions between the instrument tip and the vessel wall.