title: Diagnosis of acute pulmonary embolism in outpatients: comparison of thin-collimation multi-detector row spiral CT and planar ventilation-perfusion scintigraphy.
abstract: OBJECTIVE
  To compare multi-detector row computed tomography (CT) and ventilation-perfusion (V-P) scintigraphy in the diagnosis of acute pulmonary embolism (PE) in outpatients who were cared for in the emergency department.
  
  
  METHODS
  Ninety-four nonconsecutive patients, in whom acute PE was suspected, underwent thin-collimation multi-detector row CT (collimation, 4 x 1 mm; pitch, 1.25; scanning time, 0.5 second) and V-P scintigraphy. Concordance between CT and scintigraphic images was used in the diagnosis of PE. Pulmonary angiography was performed within 24 hours if interpretations of V-P and spiral CT images were inconclusive or discordant. Sensitivity and specificity values were calculated for V-P scintigrams and CT scans of the lungs. The rates of conclusive results for scintigraphy and CT were compared.
  
  
  RESULTS
  The sensitivity of thin-collimation multi-detector row CT and V-P scintigraphy for the detection of PE was 96% (27 of 28; CI: 82%, 99%) and 98% (65 of 66; CI: 92%, 99%), respectively. The specificity of CT and V-P scintigraphy was 86% (24 of 28; CI: 67%, 96%) and 88% (58 of 66; CI: 77%, 94%), respectively. Seven V-P scintigrams were of intermediate probability, and one spiral CT study was indeterminate. Examinations with spiral CT yielded conclusive results more often than examinations with planar V-P scintigraphy (P <.05). Five V-P scintigrams and spiral CT scans were discordant. Twelve pulmonary angiographic examinations were performed. Angiographic findings were concordant in 10 (91%) of 11 patients with conclusive CT scans in whom pulmonary angiography was attempted. CT was used to establish an alternative diagnosis in 19 (29%) of 66 patients in whom PE was excluded.
  
  
  CONCLUSIONS
  Thin-collimation multi-detector row CT is more accurate than V-P scintigraphy in the diagnosis of acute PE in outpatients. Furthermore, CT provides alternative diagnoses for patients without PE on high-quality transverse or near-isotropic reformatted images.
authors.affiliation: Department of Radiology, Cliniques Universitaires St-Luc, Université Catholique de Louvain, Av Hippocrate 10, 1200 Brussels, Belgium. coche@rdgn.ucl.ac.be
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Coche
authors.forename: Franck
authors.initials: F
authors.lastname: Verschuren
authors.forename: André
authors.initials: A
authors.lastname: Keyeux
authors.forename: Pierre
authors.initials: P
authors.lastname: Goffette
authors.forename: Louis
authors.initials: L
authors.lastname: Goncette
authors.forename: Philippe
authors.initials: P
authors.lastname: Hainaut
authors.forename: Frank
authors.initials: F
authors.lastname: Hammer
authors.forename: Edith
authors.initials: E
authors.lastname: Lavenne
authors.forename: Francis
authors.initials: F
authors.lastname: Zech
authors.forename: Philippe
authors.initials: P
authors.lastname: Meert
authors.forename: Marc S
authors.initials: MS
authors.lastname: Reynaert
mesh_terms: D000208:Acute Disease; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010045:Outpatients; D011446:Prospective Studies; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging*; D011877:Radionuclide Imaging / Q000379:methods; D012680:Sensitivity and Specificity; D036542:Tomography, Spiral Computed / Q000379:methods*