title: Factors influencing visibility and diagnostic yield of transbronchial biopsy using endobronchial ultrasound in peripheral pulmonary lesions.
abstract: OBJECTIVE
  Endobronchial ultrasound (EBUS) has increased the diagnostic yield of bronchoscopic biopsy of peripheral pulmonary lesions (PPL). However, certain lesions cannot be localized by EBUS, and the factors associated with the visibility of PPL by EBUS have not been investigated. This study evaluated the factors predicting the visualization of EBUS in PPL and the diagnostic yield of EBUS-guided transbronchial biopsy (TBB).
  
  
  METHODS
  n 2007, 83 patients with PPL underwent EBUS-guided TBB, and their medical records were reviewed and analysed retrospectively.
  
  
  RESULTS
  Of the 83 patients examined, EBUS images could not be obtained in 23 patients (28%). Lesion size was a determining factor for the visibility of PPL, with the visualization yield of EBUS in lesions <20 mm being significantly lower than that in lesions > or =20 mm (P < 0.001). A definitive diagnosis of PPL localized by EBUS was established using EBUS-guided TBB in 73% of patients. There were no significant differences in diagnostic yield related to underlying disease, lobar distribution, CT scan appearance or presence of complications. Multivariate analysis revealed that the location of PPL on CT scans and position of the probe were independent predictors of the diagnostic yield by EBUS-guided TBB (P < 0.001 and P = 0.001, respectively).
  
  
  CONCLUSIONS
  Lesion size is a significant factor predicting visualization of EBUS for PPL. The location of PPL on CT scans and position of the probe are significantly related to a higher diagnostic yield with EBUS-guided TBB.
authors.affiliation: Division of Pulmonary Medicine, Department of Internal Medicine, National Taiwan University Hospital, Yun-Lin Br, Yunlin, Taiwan.
authors.forename: Chun-Ta
authors.initials: CT
authors.lastname: Huang
authors.forename: Chao-Chi
authors.initials: CC
authors.lastname: Ho
authors.forename: Yi-Ju
authors.initials: YJ
authors.lastname: Tsai
authors.forename: Chong-Jen
authors.initials: CJ
authors.lastname: Yu
authors.forename: Pan-Chyr
authors.initials: PC
authors.lastname: Yang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy / Q000295:instrumentation / Q000379:methods; D001999:Bronchoscopy / Q000379:methods*; D019160:Endosonography / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000473:pathology; D008171:Lung Diseases / Q000000981:diagnostic imaging* / Q000473:pathology*; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D013902:Radiography, Thoracic; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D055815:Young Adult