title: Endobronchial ultrasound elastography strain ratio for mediastinal lymph node diagnosis.
abstract: BACKGROUND
  Ultrasound elastography is an imaging procedure that can assess the biomechanical characteristics of different tissues. The aim of this study was to define the diagnostic value of the endobronchial ultrasound (EBUS) elastography strain ratio of mediastinal lymph nodes in patients with a suspicion of lung cancer. The diagnostic values of the strain ratios were compared with the EBUS brightness mode (B-mode) features of selected mediastinal lymph nodes and with their cytological diagnoses.
  
  
  METHODS
  This prospective, single-centre study enrolled patients with an indication for biopsy and mediastinal staging after a non-invasive diagnostic workup of a lung tumour. EBUS with standard B-mode evaluation and elastography with strain ratio measurement were performed before endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA).
  
  
  RESULTS
  Thirty-three patients with 80 suspicious mediastinal lymph nodes were included. Malignant infiltration was confirmed in 34 (42.5%) lymph nodes. The area under the receiver operating characteristic curve for the strain ratio was 0.87 (p < 0.0001). At a strain ratio ≥ 8, the accuracy for malignancy prediction was 86.25% (sensitivity 88.24%, specificity 84.78%, positive predictive value [PPV] 81.08%, negative predictive value [NPV] 90.70%). The strain ratio is more accurate than conventional B-mode EBUS modalities for differentiating between malignant and benign lymph nodes.
  
  
  CONCLUSIONS
  EBUS-guided elastography with strain ratio assessment can distinguish malignant from benign mediastinal lymph nodes with greater accuracy than conventional EBUS modalities. This new method may reduce the number of mediastinal EBUS-TBNAs and thus reduce the invasiveness and expense of mediastinal staging in patients with non-small lung cancer (NSCLC).
authors.affiliation: University Clinic of Pulmonary and Allergic Diseases Golnik, Golnik, Slovenia.
authors.forename: Ales
authors.initials: A
authors.lastname: Rozman
authors.affiliation: University Clinic of Pulmonary and Allergic Diseases Golnik, Golnik, Slovenia.
authors.forename: Mateja Marc
authors.initials: MM
authors.lastname: Malovrh
authors.affiliation: University Clinic of Pulmonary and Allergic Diseases Golnik, Golnik, Slovenia.
authors.forename: Katja
authors.initials: K
authors.lastname: Adamic
authors.affiliation: University Clinic of Pulmonary and Allergic Diseases Golnik, Golnik, Slovenia.
authors.forename: Tjasa
authors.initials: T
authors.lastname: Subic
authors.affiliation: Institute of Oncology Ljubljana, Ljubljana, Slovenia.
authors.forename: Viljem
authors.initials: V
authors.lastname: Kovac
authors.affiliation: University Clinic of Pulmonary and Allergic Diseases Golnik, Golnik, Slovenia.
authors.forename: Matjaz
authors.initials: M
authors.lastname: Flezar
keywords: cancer staging; elastography; endobronchial ultrasound; lung cancer; needle biopsy
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