Sensor Fusion for Shape Reconstruction Using Electromagnetic Tracking Sensors and Multi-Core Optical Fiber

Optical fiber-based shape sensing is gaining popularity in cardiac catheterization lately. Typically, these procedures are taking place under the guidance of fluoroscopy. However, fluoroscopy has several disadvantages. Thanks to fiber optic shape sensing and Electromagnetic Tracking (EMT), the 3D catheter shape can now be tracked in real-time without the need for fluoroscopy. Traditional optical fiber and EMT-based shape tracking methods have the drawback of the highest shape sensing error at the tip. The information offered by the EMT sensors is used mainly to localize the estimated shape in a fixed coordinate frame. In this letter, a novel approach for tracking the catheter is introduced to address the aforementioned problem. The catheter shape is directly reconstructed in the EMT coordinate frame by approximating the catheter shape by a number of Bézier curves while taking into account the curvatures measured by the optical fiber. Both 2D and 3D shape sensing experiments are conducted. The results of the 3D experiment show that the proposed method reduces the mean shape tracking error by approximately 38% (from 12.1 mm to 5.4 mm for a sensed length of 540 mm long) compared to the traditional method where the same number of sensors are used.