title: Elastography for Predicting and Localizing Nodal Metastases during Endobronchial Ultrasound.
abstract: BACKGROUND
  Elastography is a relatively new technology that can generate images reflective of tissue stiffness (elasticity). Neoplastic tissue is usually stiffer than normal structures.
  
  
  OBJECTIVE
  The aim of this study was to evaluate the feasibility and utility of elastography when combined with convex-probe endobronchial ultrasound (CP-EBUS) for predicting and localizing metastatic lymph nodes during endobronchial ultrasound with transbronchial needle aspiration (EBUS-TBNA).
  
  
  METHODS
  Consecutive results of endobronchial elastography of lymph nodes performed using EBUS- TBNA were prospectively collected and retrospectively analyzed. Elastography images were acquired as JPEG images and also recorded as video clips. Stiff area ratios [(stiff areas as blue pixels) / (lymph node areas as region of interest pixels)] for each lymph node determined by elastography were collated with the results of pathological diagnosis. We also performed elastography of surgically resected lymph nodes and compared image findings with pathological sections.
  
  
  RESULTS
  We evaluated 49 lymph nodes in 21 patients by CP-EBUS. There were 16 metastatic nodes (10 lung cancer metastases and 6 metastases from extrathoracic malignancies). Mean stiff area ratios were significantly greater for metastatic lymph nodes (0.478) than for benign nodes (0.216; p = 0.0002). Using a cutoff value of 0.311 for stiff area ratios, the sensitivity and specificity for predicting metastatic disease were 0.81 and 0.85, respectively. The stiff area was histologically compatible with metastatic distribution in surgically resected lymph nodes.
  
  
  CONCLUSIONS
  Endobronchial elastography is feasible for lymph nodes when combined with CP-EBUS. Stiff area ratios are useful for predicting metastatic lymph nodes, which may be an efficient guide for TBNA.
authors.affiliation: Department ofGeneral Thoracic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Nakajima
authors.forename: Terunaga
authors.initials: T
authors.lastname: Inage
authors.forename: Yuuki
authors.initials: Y
authors.lastname: Sata
authors.forename: Junichi
authors.initials: J
authors.lastname: Morimoto
authors.forename: Tetsuzo
authors.initials: T
authors.lastname: Tagawa
authors.forename: Hidemi
authors.initials: H
authors.lastname: Suzuki
authors.forename: Takekazu
authors.initials: T
authors.lastname: Iwata
authors.forename: Shigetoshi
authors.initials: S
authors.lastname: Yoshida
authors.forename: Yukio
authors.initials: Y
authors.lastname: Nakatani
authors.forename: Ichiro
authors.initials: I
authors.lastname: Yoshino
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001999:Bronchoscopy / Q000379:methods*; D054459:Elasticity Imaging Techniques; D019160:Endosonography; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology / Q000601:surgery; D008207:Lymphatic Metastasis / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012680:Sensitivity and Specificity