title: Pulmonary embolism: prospective comparison of spiral CT with ventilation-perfusion scintigraphy.
abstract: OBJECTIVE
  To compare prospectively the accuracy of spiral computed tomography (CT) with that of ventilation-perfusion scintigraphy for diagnosing pulmonary embolism.
  
  
  METHODS
  Within 48 hours of presentation, 142 patients suspected of having pulmonary embolism underwent spiral CT, scintigraphy, and (when indicated) pulmonary angiography. Pulmonary angiography was attempted if interpretations of spiral CT scans and of scintigrams were discordant or indeterminate and intermediate-probability, respectively.
  
  
  RESULTS
  In the 139 patients who completed the study, interpretations of spiral CT scans and of scintigrams were concordant in 103 patients (29 with embolism, 74 without). In 20 patients, intermediate-probability scintigrams were interpreted (six with embolism at angiography, 14 without); diagnosis with spiral CT was correct in 16. Interpretations of spiral CT scans and those of scintigrams were discordant in 12 cases; diagnosis with spiral CT was correct in 11 cases and that with scintigraphy was correct in one. Spiral CT and scintigraphic scans of four patients with embolism did not show embolism. Sensitivities, specificities, and kappa values with spiral CT and scintigraphy were 87%, 95%, and 0.85 and 65%, 94%, and 0.61, respectively.
  
  
  CONCLUSIONS
  In cases of pulmonary embolism, sensitivity of spiral CT is greater than that of scintigraphy. Interobserver agreement is better with spiral CT.
authors.affiliation: Department of Radiology, Vancouver Hospital and Health Sciences Centre, British Columbia, Canada.
authors.forename: J R
authors.initials: JR
authors.lastname: Mayo
authors.forename: M
authors.initials: M
authors.lastname: Remy-Jardin
authors.forename: N L
authors.initials: NL
authors.lastname: Müller
authors.forename: J
authors.initials: J
authors.lastname: Remy
authors.forename: D F
authors.initials: DF
authors.lastname: Worsley
authors.forename: C
authors.initials: C
authors.lastname: Hossein-Foucher
authors.forename: J S
authors.initials: JS
authors.lastname: Kwong
authors.forename: M J
authors.initials: MJ
authors.lastname: Brown
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011446:Prospective Studies; D011651:Pulmonary Artery / Q000000981:diagnostic imaging; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging*; D011877:Radionuclide Imaging; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed