Phuong Toan Tran

Position control of robotic catheters inside the vasculature based on a predictive minimum energy model

Accurate and precise control of catheters inside a vasculature is a difficult yet important task. Current manual approaches require significant surgical skill. Over the years, surgeons build up a sort of mental kinematic map telling them how to handle the catheter in order to steer the catheter tip safely through the vessel system. The input-output behaviour of the catheter is complex and depends heavily on its configuration within and contacts with the vasculature. This paper introduces an alternative approach to control robotic catheters. The input-output behaviour or so-called differential kinematics are derived from a patient-specific vasculature model, following a minimum-energy argumentation. The validity of the proposed approach is demonstrated experimentally. Whereas the performance of model-based approaches is obviously greatly influenced by the correctness of estimated parameters, within this work we show experimentally how reasonable performance can already be achieved within the setup that was constructed. We expect that there is still ample room for improvement by, e.g., putting more sophisticated identification, modeling and collision detection schemes into place.

An Automatic Registration Method for Radiation-Free Catheter Navigation Guidance

Catheter navigation is typically based on fluoroscopy. This implies exposure to harmful radiation, lack of depth perception and limited soft-tissue contrast. Catheter navigation would benefit from guidance that makes better use of detailed pre-operatively acquired MR/CT images, while reducing radiation exposure and improving spatial awareness of the catheter pose and shape. A prerequisite for such guidance is an accurate registration between the catheter tracking system and the MR/CT scans. Existing registration methods are lengthy and cumbersome as they require a lot of user interaction. This forms a major obstacle for their adoption into clinical practice. This paper proposes a radiation-free registration method that minimizes the impact on the surgical workflow and avoids most user interaction. The method relies on catheters with embedded sensors that provide intra-operative data that can either belong to the vessel wall or to the lumen of the vessel. Based on the acquired surface and lumen points an accurate registration is computed automatically, with minimal user interaction. Validation of the proposed method is performed on a synthetic yet realistic aorta phantom. Input from electromagnetic tracking, force sensing, and intra-vascular ultrasound are used as intra-operative sensory data.

Intuitive Control Strategies for Teleoperation of Active Catheters in Endovascular Surgery

Cardiovascular surgeons increasingly resort to catheter-based diagnostic and therapeutic interventions because of their limited invasiveness. Although, these approaches allow treatment of patients considered unfit for conventional open surgery, exposure to radiation and high procedural complexity could lead to complications. These factors motivated the introduction of robotic technology offering more dexterous catheters, enhanced visualization and opening new possibilities in terms of guidance and coordinated control. In addition to improvements of patient outcome, through teleoperated catheter control radiation exposure of surgeons can be reduced. In order to limit surgical workload, intuitive mappings between joystick input and resulting catheter motion are essential. This paper presents and compares two proposed mappings and investigates the benefits of additional visual guidance. The comparison is based on data gathered during an experimental campaign involving 14 novices and three surgeons. The participants were asked to perform an endovascular task in a virtual reality simulator presented in the first part of this paper. Statistical results show significant superiority of one mapping with respect to the other and a significant improvement of performance thanks to additional visual guidance. Future work will focus on translating the results to a physical setup for surgical validation, also the learning effect will be analyzed more in-depth.

3D Catheter Shape Reconstruction Using Electromagnetic and Image Sensors

In current practice, fluoroscopy remains the gold standard for guiding surgeons during endovascular catheterization. The poor visibility of anatomical structures and the absence of depth informatio...

Cognitive Autonomous Catheters Operating in Dynamic Environments

Advances in miniaturized surgical instrumentation are key to less demanding and safer medical interventions. In cardiovascular procedures interventionalists turn towards catheter-based interventions, treating patients considered unfit for more invasive approaches. A positive outcome is not guaranteed. The risk for calcium dislodgement, tissue damage or even vessel rupture cannot be eliminated when instruments are maneuvered through fragile and diseased vessels. This paper reports on the progress made in terms of catheter design, vessel reconstruction, catheter shape modeling, surgical skill analysis, decision making and control. These efforts are geared towards the development of the necessary technology to autonomously steer catheters through the vasculature, a target of the EU-funded project Cognitive AutonomouS CAtheters operating in Dynamic Environments (CASCADE). Whereas autonomous placement of an aortic valve implant forms the ultimate and concrete goal, the technology of individual building blocks to reach such ambitious goal is expected to be much sooner impacting and assisting interventionalists in their daily clinical practice.