title: Novel use of pleural ultrasound can identify malignant entrapped lung prior to effusion drainage.
abstract: BACKGROUND
  The presence of entrapped lung changes the appropriate management of malignant pleural effusion from pleurodesis to insertion of an indwelling pleural catheter. No methods currently exist to identify entrapped lung prior to effusion drainage. Our objectives were to develop a method to identify entrapped lung using tissue movement and deformation (strain) analysis with ultrasonography and compare it to the existing technique of pleural elastance (PEL).
  
  
  METHODS
  Prior to drainage, 81 patients with suspected malignant pleural effusion underwent thoracic ultrasound using an echocardiogram machine. Images of the atelectatic lower lobe were acquired during breath hold, allowing motion and strain related to the cardiac impulse to be analyzed using motion mode (M mode) and speckle-tracking imaging, respectively. PEL was measured during effusion drainage. The gold-standard diagnosis of entrapped lung was the consensus opinion of two interventional pulmonologists according to postdrainage imaging. Participants were randomly divided into development and validation sets.
  
  
  RESULTS
  Both total movement and strain were significantly reduced in entrapped lung. Using data from the development set, the area under the receiver-operating curves for the diagnosis of entrapped lung was 0.86 (speckle tracking), 0.79 (M mode), and 0.69 (PEL). Using respective cutoffs of 6%, 1 mm, and 19 cm H2O on the validation set, the sensitivity/specificity was 71%/85% (speckle tracking), 50%/85% (M mode), and 40%/100% (PEL).
  
  
  CONCLUSIONS
  This novel ultrasound technique can identify entrapped lung prior to effusion drainage, which could allow appropriate choice of definitive management (pleurodesis vs indwelling catheter), reducing the number of interventions required to treat malignant pleural effusion.
authors.affiliation: From the Department of Thoracic Medicine, The Princess Alexandra Hospital, Brisbane, QLD, Australia. Electronic address: mattsalamonsen@gmail.com.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Salamonsen
authors.affiliation: Department of Cardiology, The Princess Alexandra Hospital, Brisbane, QLD, Australia.
authors.forename: Ada K C
authors.initials: AKC
authors.lastname: Lo
authors.affiliation: Royal Brisbane and Women's Hospital and Department of Cardiology, The Princess Alexandra Hospital, Brisbane, QLD, Australia.
authors.forename: Arnold C T
authors.initials: ACT
authors.lastname: Ng
authors.affiliation: From the Department of Thoracic Medicine, The Princess Alexandra Hospital, Brisbane, QLD, Australia.
authors.forename: Farzad
authors.initials: F
authors.lastname: Bashirzadeh
authors.affiliation: Royal Brisbane and Women's Hospital and Department of Cardiology, The Princess Alexandra Hospital, Brisbane, QLD, Australia.
authors.forename: William Y S
authors.initials: WYS
authors.lastname: Wang
authors.affiliation: From the Department of Thoracic Medicine, The Princess Alexandra Hospital, Brisbane, QLD, Australia.
authors.forename: David I K
authors.initials: DIK
authors.lastname: Fielding
mesh_terms: D000368:Aged; D003937:Diagnosis, Differential; D004322:Drainage / Q000379:methods*; D004548:Elasticity; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D010994:Pleura / Q000000981:diagnostic imaging* / Q000503:physiopathology; D016066:Pleural Effusion, Malignant / Q000000981:diagnostic imaging* / Q000628:therapy; D011446:Prospective Studies; D012372:ROC Curve; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014463:Ultrasonography