Image-based Contact Detection and Static Force Estimation on Steerable RFA Catheters

Real-time force estimation is crucial for robot-assisted radio frequency ablation procedures to perform safe and effective treatment. This study proposes an image-based method for real-time force estimation on steerable catheters. To this end, first a planar mechanical model of the catheter with an unknown contact force with the endocardium was developed. Afterward, an inverse solution schema based on the deformed shape of the catheter was proposed and verified. To validate the proposed method, finite element simulation was used to obtain the deformed shape of a typical catheter with 0.5-5 N contact force. The results of the proposed image-based force estimation were in fair agreement with reference values. The absolute estimation error was less than 5% for all forces and the goodness-of-fit between estimation and reference was R² = 0.97. The proposed method was in compliance with the accuracy and speed requirements for robot-assisted cardiac ablation procedures.