title: Improving diagnostic accuracy in assessing pulmonary edema on bedside chest radiographs using a standardized scoring approach.
abstract: BACKGROUND
  To assess the value of a score-based system which allows standardized evaluation of pulmonary edema on bedside chest radiographs (CXRs) under routine clinical conditions.
  
  
  METHODS
  Seven experienced readers assessed bedside CXRs of ten patients with an extravascular lung water (EVLW)-value of ≤ 8 mL/kg (range: 4-8 mL/kg; indicates no pulmonary edema) and a series of ten patients with an EVLW-value of ≥ 15 mL/kg (range: 15-21 mL/kg; = indicates a pulmonary edema) with and without customized software which would permit a standardized assessment of the various indications of pulmonary edema. The software provides a score that identifies patients with and without pulmonary edema. EVLW-values were measured instantly after bedside CXR imaging using a pulse contour cardiac output (PiCCO) system and served as a reference standard. The patients were non-traumatic and not treated with diuretics or dobutamine during bedside CXR imaging and the PiCCO measurements. Mean sensitivity, specificity, positive and negative predictive value, the percentage of overall agreement and the free-marginal multirater kappa value was calculated for both the standard and the standardized score-based approach. The net reclassification index was calculated for each reader as well as for all readers.
  
  
  RESULTS
  Evaluation of bedside CXRs by means of the score-based approach took longer (23 ± 12 seconds versus 7 ± 3 seconds without the use of the software) but improved radiologists' sensitivity (from 57 to 77%), specificity (from 90 to 100%) and the free-marginal multirater kappa value (from 0.34 to 0.68). The positive predictive value was raised from 85 to 100% and the negative predictive value from 68 to 81%. A net reclassification index of 0.3 (all readers) demonstrates an improvement in prediction performance gained by the score-based approach. The percentage of overall agreement was 67% with the standard approach and 84% with the software-based approach.
  
  
  CONCLUSIONS
  The diagnostic accuracy of bedside CXRs to discriminate patients with elevated EVLW-values from those with a normal value can be improved with the use of a standardized score-based approach. The investigated system is freely available as a web-based application (accessible via: http://www.radiologie.uk-erlangen.de/aerzte-und-zuweiser/edema).
authors.affiliation: Department of Radiology, University Hospital Erlangen, Maximiliansplatz 1, 91054 Erlangen, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Hammon
authors.affiliation: Department of Radiology, University Hospital Erlangen, Maximiliansplatz 1, 91054 Erlangen, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Dankerl
authors.affiliation: Department of Radiology, Hospital Ansbach, Escherichstrasse 1, 91522 Ansbach, Germany.
authors.forename: Heinz Leonhard
authors.initials: HL
authors.lastname: Voit-Höhne
authors.affiliation: Department of Radiology, University Hospital Erlangen, Maximiliansplatz 1, 91054 Erlangen, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Sandmair
authors.affiliation: Department of Radiology, University Hospital Erlangen, Maximiliansplatz 1, 91054 Erlangen, Germany.
authors.forename: Ferdinand Josef
authors.initials: FJ
authors.lastname: Kammerer
authors.affiliation: Department of Radiology, University Hospital Erlangen, Maximiliansplatz 1, 91054 Erlangen, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Uder
authors.affiliation: Department of Radiology, University Hospital Erlangen, Maximiliansplatz 1, 91054 Erlangen, Germany.
authors.forename: Rolf
authors.initials: R
authors.lastname: Janka
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002302:Cardiac Output / Q000502:physiology; D015633:Extravascular Lung Water / Q000378:metabolism; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D019095:Point-of-Care Systems; D011654:Pulmonary Edema / Q000000981:diagnostic imaging*; D013902:Radiography, Thoracic; D012015:Reference Standards; D015203:Reproducibility of Results; D012984:Software
keywords: Bedside chest radiograph; Extravascular lung water (EVLW); Pulmonary edema; Scoring system; Web-based application