Catheter contact force estimation from shape detection using a real-time Cosserat rod model

This paper proposes a novel Cosserat rod model based method to estimate contact forces based on the shape analysis of the catheter. We simplify the original Cosserat rod model to achieve real-time estimation of the force magnitude and directions applied to the catheter tip. The simplified model contains a set of arithmetic equations, which can be rapidly solved using an iterative optimization algorithm. Experimental evaluation shows that the computational frequency of the force estimation was found to be 33.7Hz. Both the magnitude and the direction of the contact force were accurately estimated. The accuracy of the estimations of magnitude was 89.50%, and for the contact direction was 88.13%. Mean errors of the contact force and the contact angle are 7 × 10^-4N and 0.931 degree respectively. To prove the concept, the catheter shape is detected through a RGB camera. However, the proposed method can be easily applied to existing catheter gating and detecting methods using the medical imaging environments such as X-ray fluoroscopy, CT, ultrasound, magnetic field and MRI. The results of evaluation experiments demonstrate what the proposed method is promising for force estimation without the need of a physical force sensor in various types of catheter tips.