title: The efficacy of chest radiographs in detecting parapneumonic effusions.
abstract: OBJECTIVE
  Current guidelines recommend parapneumonic effusions (PPEs) with a thickness of ≥ 10 mm be sampled via thoracentesis. We hypothesized that anteroposterior (AP) CXRs are not as sensitive as posteroanterior (PA) and lateral radiographs in identifying PPEs and should not be routinely used in patients with suspected pneumonia.
  
  
  METHODS
  Sixty-one hospitalized patients with pneumonia and PPE were retrospectively studied, all of whom had a CXR and CT scan within 24 h of each other. The CXRs of these patients were independently read by three pulmonologists for an effusion in each hemithorax, which was correlated with measured pleural fluid thickness on chest CT.
  
  
  RESULTS
  Lateral, PA and AP radiographs were equivalent in identifying the presence of PPEs. All three views missed more than 10% of PPEs. The sensitivities of lateral, PA and AP CXRs were 85.7%, 82.1% and 78.4%, respectively (P = 0.749); the specificity was 87.5%, 81.3% and 76.4%, respectively (P = 0.198). The majority of effusions missed in each view were on films with lower lobe consolidation.
  
  
  CONCLUSIONS
  All three CXR views missed effusions of a size significant enough to warrant thoracentesis. Consideration should be given to obtaining additional imaging at the time patients present with pneumonia, particularly in those with lower lobe consolidation.
authors.affiliation: Division of Allergy, Pulmonary, and Critical Care Medicine, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2650, USA. anupama.brixey@vanderbilt.edu
authors.forename: Anupama G
authors.initials: AG
authors.lastname: Brixey
authors.forename: Yifeng
authors.initials: Y
authors.lastname: Luo
authors.forename: Vasileios
authors.initials: V
authors.lastname: Skouras
authors.forename: Anna
authors.initials: A
authors.lastname: Awdankiewicz
authors.forename: Richard W
authors.initials: RW
authors.lastname: Light
mesh_terms: D000328:Adult; D000368:Aged; D003951:Diagnostic Errors; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010996:Pleural Effusion / Q000175:diagnosis / Q000000981:diagnostic imaging*; D011014:Pneumonia / Q000175:diagnosis / Q000000981:diagnostic imaging*; D013902:Radiography, Thoracic / Q000379:methods*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*