title: Diagnostic accuracy of sonography for pleural effusion: systematic review.
abstract: OBJECTIVE
  The initial method for evaluating the presence of pleural effusion was chest radiography. Isolated studies have shown that sonography has greater accuracy than radiography for this diagnosis; however, no systematic reviews on this matter are available in the literature. Thus, the aim of this study was to evaluate the accuracy of sonography in detecting pleural effusion, by means of a systematic review of the literature.
  
  
  METHODS
  This was a systematic review with meta-analysis on accuracy studies. This study was conducted in the Department of Diagnostic Imaging and in the Brazilian Cochrane Center, Discipline of Emergency Medicine and Evidence-Based Medicine, Department of Medicine, Universidade Federal de São Paulo (Unifesp), São Paulo, Brazil.
  
  
  METHODS
  The following databases were searched: Cochrane Library, Medline, Web of Science, Embase and Literatura Latino-Americana e do Caribe em Ciências da Saúde (Lilacs). The references of relevant studies were also screened for additional citations of interest. Studies in which the accuracy of sonography for detecting pleural effusion was tested, with an acceptable reference standard (computed tomography or thoracic drainage), were included.
  
  
  RESULTS
  Four studies were included. All of them showed that sonography had high sensitivity, specificity and accuracy for detecting pleural effusions. The mean sensitivity was 93% (95% confidence interval, CI: 89% to 96%), and specificity was 96% (95% CI: 95% to 98%).
  
  
  CONCLUSIONS
  In different populations and clinical settings, sonography showed consistently high sensitivity, specificity and accuracy for detecting fluid in the pleural space.
authors.affiliation: Department of Diagnostic Imaging, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil. agrimberg@gmail.com
authors.forename: Alexandre
authors.initials: A
authors.lastname: Grimberg
authors.forename: David Carlos
authors.initials: DC
authors.lastname: Shigueoka
authors.forename: Alvaro Nagib
authors.initials: AN
authors.lastname: Atallah
authors.forename: Sergio
authors.initials: S
authors.lastname: Ajzen
authors.forename: Wagner
authors.initials: W
authors.lastname: Iared
mesh_terms: D006801:Humans; D010996:Pleural Effusion / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014463:Ultrasonography