title: Accuracy of X-ray with perfusion scan in young patients with suspected pulmonary embolism.
abstract: BACKGROUND
  Computed tomography pulmonary angiogram (CTPA) has become the standard test in the diagnostic workup of patients with suspected pulmonary embolism (PE). However, young patients may have an increased risk of cancer with CTPA. Perfusion scanning combined with chest X-ray (X/Q) may offer an adequate alternative, but has never been prospectively validated. We directly compared this strategy with CTPA in patients aged ≤50years with suspected PE.
  
  
  METHODS
  Consecutive patients with a likely clinical probability or an abnormal D-dimer level underwent both CTPA and X/Q. Two trained and experienced nuclear physicians independently analyzed the X/Q-scans. The accuracy of X/Q according to the PISAPED criteria was calculated in terms of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV).
  
  
  RESULTS
  Seventy-six patients were included, with a PE rate of 33%. The inter-observer agreement for X/Q-scan reading was high (κ=0.89). After consensus reading, 21 patients (28%) were categorized as 'PE present', 53 (70%) as 'PE absent', and two (2.6%) as 'non-diagnostic'. In 22%, there was a discrepancy between the X/Q-scan and CPTA for the diagnosis or exclusion of PE. The PPV and NPV were 71% and 83%, respectively.
  
  
  CONCLUSIONS
  In patients with a high risk of PE, a diagnostic strategy of chest X-ray and perfusion scanning using the PISAPED criteria seems less safe than CTPA. Additional studies should further investigate this diagnostic algorithm.
authors.affiliation: Department of Vascular Medicine, Academic Medical Center, Amsterdam, The Netherlands. Electronic address: j.vanes@olvg.nl.
authors.forename: J
authors.initials: J
authors.lastname: van Es
authors.affiliation: Department of Vascular Medicine, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: R A
authors.initials: RA
authors.lastname: Douma
authors.affiliation: Department of Nuclear Medicine, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: R E L
authors.initials: RE
authors.lastname: Hezemans
authors.affiliation: Department of Emergency Medicine, Cliniques Universitaires St-Luc, Brussels, Université Catholique de Louvain, Belgium.
authors.forename: A
authors.initials: A
authors.lastname: Penaloza
authors.affiliation: Department of Internal Medicine, Erasme Hospital, Brussels, Belgium.
authors.forename: S
authors.initials: S
authors.lastname: Motte
authors.affiliation: Department of Clinical Epidemiology, School for Public Health and Primary Care (CAPHRI), Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: P G M
authors.initials: PG
authors.lastname: Erkens
authors.affiliation: Department of Internal Medicine, Erasmus Hospital, Rotterdam, The Netherlands.
authors.forename: M F
authors.initials: MF
authors.lastname: Durian
authors.affiliation: Department of Nuclear Medicine, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: B L F
authors.initials: BL
authors.lastname: van Eck-Smit
authors.affiliation: Department of Vascular Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: P W
authors.initials: PW
authors.lastname: Kamphuisen
mesh_terms: D005260:Female; D006801:Humans; D008297:Male; D055420:Perfusion Imaging / Q000379:methods*; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging*; D011859:Radiography; D014964:X-Ray Therapy / Q000379:methods*