Compensation of Dynamic Electromagnetic Field Distortion Using Simultaneous Localization and Mapping Method with Application in Endobronchial Ultrasound‐Transbronchial Needle Aspiration (EBUS‐TBNA) Guidance

BACKGROUND: Electromagnetic (EM)-based navigation methods without line-of-sight restrictions may improve lymph node sampling precision in transbronchial needle aspiration (TBNA) procedure. However, EM tracking susceptibility to metallic objects severely declines its precision. METHOD: We proposed to track the location of a tool in a dynamic bronchial phantom and compensate field distortion in a real-time procedure. Extended Kalman filter simultaneous localization and mapping (EKF-SLAM) algorithm employ the bronchial motion and observations of a redundant sensor. The proposed approach was applied to the phantom with four different amplitudes of breathing motion in the presence of two types of field-distorting objects. RESULTS: The proposed approach improved the accuracy of EM tracking on average from 18.94 +/-1.17 mm to 4.59 +/-0.29 mm and from 14.2 +/-0.69 mm to 4.31 +/-0.18mm in the presence of steel and aluminum, respectively. CONCLUSIONS: With EM tracking position error reduction based on the EKF-SLAM technique, the approach is appeared promising for a navigated ultrasound TBNA procedure.