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.