Late-breaking abstract: Radial probe endobrnchial ultrasound scanning assessing invasion depth of central lesions in the tracheobronchial wall

Background: Patients with central tracheobronchial benign or malignant lesions who have not recieved surgical treatment can be treated by interventional techniques. The accuracy of the invasion depth of central lesion in tracheobronchial wall plays an important role in making interventional treatment plan. This study used radial probe endobronchial ultrasound (EBUS) scanning to evaluate the accuracy of the invasion depth of central tracheobronchial lesions, and the influence of EBUS scanning in treatment plan making and guidance. Methods: A radial ultrasonic probe with a balloon sheath was introduced through the channel of a flexible bronchoscope. The balloon at the tip of the probe was inflated with distilled water until coupling with the airway wall under endoscopic control. The circular image of EBUS, which revealed the layered structure of the tracheobronchial wall, could be achieved. Results: Total of 125 patients were enrolled in the study. 30 patients underwent surgical operation and pathologically proved the EBUS diagnosis accuracy of 90% (27/30), sensitivity and specificity were 88.89% (24/27) and 100 (3/3) respectively. In response to EBUS images, 40 approaches were altered or guided: lymph-node metastasis and compressive lesions was diagnosed by EBUS-guided transbronchial needle aspiration (n=8); Lesions ablation with laser or electricity were stopped when EBUS demonstrated close range with vessels or perforation possibility (n=13), stents size were changed (n=14), operation was canceled (n=3) and foreign body was removed (n=2). Conclusions: EBUS can be a useful tool in assessing the central lesion invasion to the tracheobronchial wall.