title: Radial probe endobronchial ultrasound scanning assessing invasive depth of central lesions in tracheobronchial wall.
abstract: BACKGROUND
  Patients with central tracheobronchial benign or malignant lesions who have not recieved surgical treatment can be treated by interventional techniques, such as laser, afterloading radiotherapy, cryotherapy, photodynamics treatment, radiofrequency ablation and stenting, etc. The accuracy of the invasive depth of central lesion in tracheobronchial wall plays an important role in making interventional treatment plan. This study used radial probe endobronchial ultrasound (RP-EBUS) scanning to evaluate the accuracy of the invasive depth of central lesions in tracheobronchial wall, and the influence of RP-EBUS scanning in treatment plan making and guidance.
  
  
  METHODS
  This was a prospective study of consecutive patients with central tracheobronchial lesions found by CT or bronchoscopy. We performed EBUS scanning after common bronchoscopy under local anesthesia. A radial ultrasonic probe (2.0 mm in diameter with 20-MHz frequency) with a balloon sheath was introduced through the 2.8-mm-diameter 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. Thirty patients underwent surgical operation and pathologically proved the RP-EBUS diagnosis accuracy of tumor invasive depth in tracheobroncial wall was 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 (TBNA) (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). No complication associated with the use of EBUS was observed.
  
  
  CONCLUSIONS
  RP-EBUS can be a useful tool in assessing the central lesion invasive depth to the tracheobronchial wall.
authors.affiliation: Department of Respiratory, Guangdong General Hospital and Guangdong Academy of Medical Science, Guangzhou, Guangdong 510080, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.forename: Ping-Ping
authors.initials: PP
authors.lastname: Chen
authors.forename: Yu
authors.initials: Y
authors.lastname: Huang
authors.forename: Zheng-Xian
authors.initials: ZX
authors.lastname: Chen
mesh_terms: D001980:Bronchi / Q000000981:diagnostic imaging* / Q000473:pathology*; D001984:Bronchial Neoplasms / Q000473:pathology; D001999:Bronchoscopy / Q000379:methods*; D006801:Humans; D009361:Neoplasm Invasiveness; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed; D014132:Trachea / Q000000981:diagnostic imaging* / Q000473:pathology*; D014463:Ultrasonography