Expert opinion of mediastinal lymph node positions from an intrabronchial view

Kjetil Roth, Tomas Eagan, Jon Hardie

The knowledge of the mediastinal lymph node positions from an intrabronchial view was important for conventional transbronchial needle aspiration (TBNA). The introduction of endobronchial ultrasound guided transbronchial needle aspiration (EBUS-TBNA) changed the focus from the intrabronchial landmarks to the real life ultrasound images. However when all EBUS reachable lymph nodes are evaluated (mapping), the knowledge of the intrabronchial positions is crucial. The objective of this study was to present a new expert opinion map from an intrabronchial perspective validated by an interobserver variation analysis. Physicians who had performed more than 30 EBUS-TBNA were included. They marked areas for optimal TBNA sampling on standardized pictures from an intrabronchial perspective. Areas marked by more than 3 of the 14 experts who had performed more than 1000 EBUS provided the data for the map. The map was validated among the experts and the agreement was compared to the agreement among less experienced physicians. There was high agreement (>80 %) among the experts in lymph node positions 4 L, 7, 10 L, 11R and 11 L. The agreement for 4R and 10R was low (<70 %). The agreement among the most experienced physicians was significantly higher than the less experienced physicians in station 10 L (92 % vs. 50 %, p:0.01). It was possible to present a new map of expert opinion for optimal sampling positions in lymph node stations 4 L, 4R, 7, 10 L, 11R and 11 L. All positions except 4R had high agreement. No area was covered by more than 3 of the 14 experts in station 10R.