Automated pointing of cardiac imaging catheters

Abstract

Intracardiac echocardiography (ICE) catheters enable high-quality ultrasound imaging within the heart, but their use in guiding procedures is limited due to the difficulty of manually pointing them at structures of interest. This paper presents the design and testing of a catheter steering model for robotic control of commercial ICE catheters. The four actuated degrees of freedom (4-DOF) are two catheter handle knobs to produce bi-directional bending in combination with rotation and translation of the handle. An extra degree of freedom in the system allows the imaging plane (dependent on orientation) to be directed at an object of interest. A closed form solution for forward and inverse kinematics enables control of the catheter tip position and the imaging plane orientation. The proposed algorithms were validated with a robotic test bed using electromagnetic sensor tracking of the catheter tip. The ability to automatically acquire imaging targets in the heart may improve the efficiency and effectiveness of intracardiac catheter interventions by allowing visualization of soft tissue structures that are not visible using standard fluoroscopic guidance. Although the system has been developed and tested for manipulating ICE catheters, the methods described here are applicable to any long thin tendon-driven tool (with single or bi-directional bending) requiring accurate tip position and orientation control.

A 4-DOF Robot for Positioning Ultrasound Imaging Catheters

“…To increase the utility of these high-quality imaging devices, we developed a robotic system for automatically guiding US imaging catheters within the heart [3-5]. The system was used to demonstrate millimeter-level positioning accuracy and sub-degree-level angular steering accuracy in bench-top experiments.…”

Algorithms for Automated Pointing of Cardiac Imaging Catheters

“…Several kinematic strategies focused on catheter positioning have already been developed, and we will use these techniques as the basis of our approach to control the ICE catheter [9][10][11][12]. Additionally, researchers have also described the bending characteristics of long deformable objects, sometimes described as remotely actuated continuum robots [13,14].…”

“…Specifically, the kinematics presented by Loschak et al in [9] model the relationship between the joint space control knobs and the task space US imaging plane positions and orientations. This model, which serves as the basis for our investigation, is based on geometric principles and classic robot kinematics.…”

“…It is assumed that applying pitch then yaw will yield the same kinematic results as applying yaw then pitch. These claims were validated in [9].…”

“…While some systems offer limited Cartesian control, these systems do not feature orientation control which is essential for aiming an imager. This paper expands upon the system presented by researchers Loschak et al to demonstrate more accurate position and 1-DOF orientation control [9]. Next, algorithms for visualization strategies are created in conjunction with the bending model.…”