title: Perfusion abnormalities in pulmonary embolism studied with perfusion MRI and ventilation-perfusion scintigraphy: an intra-modality and inter-modality agreement study.
abstract: OBJECTIVE
  To compare perfusion magnetic resonance imaging (MRI) and ventilation-perfusion scintigraphy (V-P scan) in the study of perfusion abnormalities in pulmonary embolism (PE) and to compare the PE results to the findings previously reported for pneumonia and chronic obstructive pulmonary disease (COPD), in terms of perfusion abnormalities.
  
  
  METHODS
  Dynamic contrast-enhanced MR images and V-P scans of 20 patients with PE, 11 patients with acute pneumonia, and 13 patients with exacerbation of COPD were studied. Five categories of perfusion abnormalities within each imaging modality were defined. Intra- and inter-modality agreement (kappa values) in the evaluation of perfusion abnormalities were calculated, based on the two observers of each imaging modality (all blinded to each other and true diagnosis). Finally, three categories of perfusion MRI diagnosis (PE, pneumonia, and COPD) were also defined and the inter-observer agreement (kappa value) was calculated.
  
  
  RESULTS
  For PE, the intra-modality agreement (kappa value) in the evaluation of perfusion abnormalities was 0.77 for MRI and 0.65 for V-P scan. The inter-modality agreement varied from 0.52 to 0.57, respectively, and was observer-dependent. For the pooled group of PE, pneumonia, and COPD, the intra-modality agreement of perfusion abnormalities was 0.76 for MRI and 0.65 for V-P scan, and the inter-modality agreement varied from 0.51 to 0.56. The kappa value for inter-observer agreement for MRI diagnosis was 0.92.
  
  
  CONCLUSIONS
  Evaluation of perfusion abnormalities in PE, pneumonia, and COPD using perfusion MRI and V-P scan showed a high intra-modality agreement that was higher than the inter-modality agreement. Further studies are now needed in patients presenting with possible PE to evaluate the sensitivity and specificity of the method.
authors.affiliation: Department of Medicine, University Hospital of Trondheim, Norwegian University of Science and Technology, Trondheim, Norway. Tore.Amundsen@medisin.ntnu.no
authors.forename: Tore
authors.initials: T
authors.lastname: Amundsen
authors.forename: Geir
authors.initials: G
authors.lastname: Torheim
authors.forename: Kjell A
authors.initials: KA
authors.lastname: Kvistad
authors.forename: Anders
authors.initials: A
authors.lastname: Waage
authors.forename: Leif
authors.initials: L
authors.lastname: Bjermer
authors.forename: Knut K
authors.initials: KK
authors.lastname: Nordlid
authors.forename: Harald
authors.initials: H
authors.lastname: Johnsen
authors.forename: Arne
authors.initials: A
authors.lastname: Asberg
authors.forename: Olav
authors.initials: O
authors.lastname: Haraldseth
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004058:Diffusion; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D011014:Pneumonia / Q000175:diagnosis; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis; D011655:Pulmonary Embolism / Q000175:diagnosis* / Q000000981:diagnostic imaging*; D011877:Radionuclide Imaging; D014692:Ventilation-Perfusion Ratio