title: Quantification of pleural effusions: sonography versus radiography.
abstract: OBJECTIVE
  To develop a practical method of estimating the volume of pleural effusions with sonography.
  
  
  METHODS
  Fifty-one patients underwent sonography of the pleural space while supine. Sonographic results and results of lateral decubitus radiography were compared with actual effusion volumes. The maximum thickness of the pleural fluid layer was measured with both modalities, while actual effusion volume was determined by means of complete drainage.
  
  
  RESULTS
  Sonographic measurements correlated statistically significantly better with actual effusion volume (r = .80) than did radiographic measurements (r = .58) (P < or = .05). With sonographic measurement, an effusion width of 20 mm had a mean volume of 380 mL +/- 130 (standard deviation), while one of 40 mm had a mean volume of 1,000 mL +/- 330. Prediction error with sonographic measurement (mean, 224 mL) was statistically significantly less (P < or = .002) than that with radiographic measurement (mean, 465 mL).
  
  
  CONCLUSIONS
  In quantification of pleural effusions, the sonographic measurement method presented is preferable to radiographic measurement.
authors.affiliation: Department of Radiology, University of Vienna, Austria.
authors.forename: K L
authors.initials: KL
authors.lastname: Eibenberger
authors.forename: W I
authors.initials: WI
authors.lastname: Dock
authors.forename: M E
authors.initials: ME
authors.lastname: Ammann
authors.forename: R
authors.initials: R
authors.lastname: Dorffner
authors.forename: M F
authors.initials: MF
authors.lastname: Hörmann
authors.forename: F
authors.initials: F
authors.lastname: Grabenwöger
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003951:Diagnostic Errors; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010996:Pleural Effusion / Q000000981:diagnostic imaging* / Q000628:therapy; D011237:Predictive Value of Tests; D013902:Radiography, Thoracic; D013909:Thorax / Q000000981:diagnostic imaging; D014463:Ultrasonography