Development and Control of a Dual-Mode Magnetic Intravascular Ultrasound Robot for Imaging in Tortuous Blood Vessels

Atherosclerosis accounts for over 30% of global deaths annually. The intravascular ultrasound (IVUS) can provide detailed information on lesions, enabling accurate diagnosis, and treatment of vascular diseases. The existing IVUS catheters face challenges to work in tortuous blood vessels. This study presents a dual-mode magnetic IVUS robot, featuring by miniature size and high softness, which allows for intravascular imaging in hard-to-reach regions. First, the magnetic IVUS robot consisting of an acoustic-magnetic tip and a soft catheter is designed, which performs: 1) controllable bending under static magnetic fields to navigate in complex vasculature; 2) shaft-free acoustic beam scanning under dynamic magnetic fields to provide high-resolution ultrasound images. Then, the motion modeling of navigating mode and imaging mode are analyzed, respectively. Next, an integrated system and actuating strategy are established, realizing the dual-mode decoupling control of the magnetic IVUS robot. Finally, the effectiveness of the presented method is validated in vascular models, imaging phantoms, and in-vitro porcine artery vessel. The designed magnetic IVUS robot achieves dual objectives, including active angle steering at bifurcations and acoustic beam scanning at lesions, simultaneously improving the operating flexibility and imaging stability. The proposed design and control scheme demonstrate the feasibility of tortuous intravascular imaging, providing a potential solution for clinical applications.