title: "Ultrasound comet-tail images": a marker of pulmonary edema: a comparative study with wedge pressure and extravascular lung water.
abstract: BACKGROUND
  Echographic examination of the lung surface may reveal multiple "comet-tail images" originating from water-thickened interlobular septa. These images could be useful for noninvasive assessment of interstitial pulmonary edema.
  
  
  OBJECTIVE
  The purpose of this study was to assess the diagnostic accuracy of lung comet-tail images compared with chest radiography, wedge pressure, and extravascular lung water (EVLW) quantified by the indicator dilution method (PiCCO System, version 4.1; Pulsion Medical Systems; Munich, Germany).
  
  
  METHODS
  We enrolled 20 patients (mean age, 62.6 +/- 11.5 years [+/- SD]). Patients were studied before, immediately after, and 24 h following cardiac surgery with chest ultrasound, chest radiography, pulmonary artery catheterization, and the PiCCO system. Performing echo scanning (right and left hemithorax, from second to fourth intercostal space, from parasternal to midaxillary line), an individual patient comet score was obtained by summing the number of comets in each scanned space.
  
  
  RESULTS
  A total of 60 comparisons were obtained. Significant positive linear correlations were found between comet score and EVLW determined by the PiCCO System (r = 0.42, p = 0.001), between comet score and wedge pressure (r = 0.48, p = 0.01), and between comet score and radiologic lung water score (r = 0.60, p = 0.0001).
  
  
  CONCLUSIONS
  The presence and the number of comet-tail images provide reliable information on interstitial pulmonary edema. Therefore, ultrasonography represent an attractive, easy-to-use, bedside diagnostic tool for assessing cardiac function and pulmonary congestion.
authors.affiliation: Division of Non-Invasive Cardiology, Cardiothoracic Department, San Raffaele Hospital, Istituto di Richerche e Cura a carattere Scientifico, Milano, Italy. agricola.eustachio@hsr.it <agricola.eustachio@hsr.it>
authors.forename: Eustachio
authors.initials: E
authors.lastname: Agricola
authors.forename: Tiziana
authors.initials: T
authors.lastname: Bove
authors.forename: Michele
authors.initials: M
authors.lastname: Oppizzi
authors.forename: Giovanni
authors.initials: G
authors.lastname: Marino
authors.forename: Alberto
authors.initials: A
authors.lastname: Zangrillo
authors.forename: Alberto
authors.initials: A
authors.lastname: Margonato
authors.forename: Eugenio
authors.initials: E
authors.lastname: Picano
mesh_terms: D000368:Aged; D015633:Extravascular Lung Water; D005260:Female; D006801:Humans; D007201:Indicator Dilution Techniques; D008297:Male; D008875:Middle Aged; D011654:Pulmonary Edema / Q000000981:diagnostic imaging*; D011669:Pulmonary Wedge Pressure; D012680:Sensitivity and Specificity; D014463:Ultrasonography