An electromagnetic navigation system for transbronchial interventions with a novel approach to respiratory motion compensation
Custom built electromagnetically tracked TBNA needle. (a) Disassembled needle and EMT sensor. (b) Reassembled needle with the EMT sensor affixed to the lower end of the needle tip. (c) Luer-Lock at the end of the needle with the EMT sensor cable.
Screenshot of the navigation software providing guidance for TBNA interventions by a four-field view. (1) 2D transversal view of the CT image with the TBNA needle position superimposed in red. (2) 3D global view with surface representation of the tracheobronchial tree and the position of the bronchoscope tip (green cone) and the TBNA needle. (3) Video image provided by the bronchoscope. (4) Virtual bronchoscopy view with path to the target region (yellow) and TBNA needle position in red.
ArtiChest™ thorax phantom. (a) Schematic design and (b) real setup with inflated lung and bronchoscope inserted in the left lower lung lobe.
Setup for the experiments in the CT intervention room.
Schematic illustration of the workflow for each experiment. The preoperative planning scan was only performed once per lung. The following steps were repeated for each TBNA intervention.
Tracked bronchoscope positions depicted by spheres with motion compensation on and off. (a) Shows the correct match for intervention #8. (b) Visualizes intervention #12 where the motion compensation filter failed and falsely corrected the bronchoscope positions into a neighboring bronchus.
Results for intervention #14 for bronchoscope and TBNA needle tracking with motion compensation on and off.
(a) Bronchoscope and (b) TBNA mean targeting error (MTE) plotted against the insertion depth relative to the main carina. (c) TBNA mean targeting error plotted against needle insertion depth relative to the bronchoscope tip. Circles represent the interventions #3, #6, and #12 where the motion compensation filter falsely corrected the bronchoscope positions to a neighboring bronchus.
Mean error statistic calculated from all 18 interventions, according to Sec. II C.
Fiducial registration error (FRE) as defined in Sec. II C for each single intervention and mean targeting error (MTEB) for bronchoscope tracking with respiratory motion compensation on and off, respectively. The percentages of the bronchoscope positions that were located in the correct bronchus (verified by the control CT image) are also reported.
Mean targeting error (MTET) as defined in Sec. II C for TBNA needle tracking with respiratory motion compensation on and off, respectively. The TBNA needle insertion depth measured from the tip of the bronchoscope is also reported as well as the percentages of the bronchoscope positions that were located in the correct bronchus (verified by the control CT image).
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