title: Influence of Sinogram-Affirmed Iterative Reconstruction on Computed Tomography-Based Lung Volumetry and Quantification of Pulmonary Emphysema.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the influence of sinogram-affirmed iterative reconstruction (SAFIRE) on quantification of lung volume and pulmonary emphysema in low-dose chest computed tomography compared with filtered back projection (FBP).
  
  
  METHODS
  Enhanced or nonenhanced low-dose chest computed tomography was performed in 20 patients with chronic obstructive pulmonary disease (group A) and in 20 patients without lung disease (group B). Data sets were reconstructed with FBP and SAFIRE strength levels 3 to 5. Two readers semiautomatically evaluated lung volumes and automatically quantified pulmonary emphysema, and another assessed image quality. Radiation dose parameters were recorded.
  
  
  RESULTS
  Lung volume between FBP and SAFIRE 3 to 5 was not significantly different among both groups (all P > 0.05). When compared with those of FBP, total emphysema volume was significantly lower among reconstructions with SAFIRE 4 and 5 (mean difference, 0.56 and 0.79 L; all P < 0.001). There was no nondiagnostic image quality.
  
  
  CONCLUSIONS
  Sinogram-affirmed iterative reconstruction does not alter lung volume measurements, although quantification of lung emphysema is affected at higher strength levels.
authors.affiliation: From the *Institute of Diagnostic and Interventional Radiology, and †Division of Thoracic Surgery, University Hospital Zurich, Switzerland.
authors.forename: Stephan
authors.initials: S
authors.lastname: Baumueller
authors.forename: Regina
authors.initials: R
authors.lastname: Hilty
authors.forename: Thi Dan Linh
authors.initials: TD
authors.lastname: Nguyen
authors.forename: Walter
authors.initials: W
authors.lastname: Weder
authors.forename: Hatem
authors.initials: H
authors.lastname: Alkadhi
authors.forename: Thomas
authors.initials: T
authors.lastname: Frauenfelder
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D003287:Contrast Media; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008168:Lung / Q000000981:diagnostic imaging / Q000473:pathology; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D009929:Organ Size; D011446:Prospective Studies; D011656:Pulmonary Emphysema / Q000000981:diagnostic imaging* / Q000473:pathology; D011856:Radiographic Image Enhancement / Q000379:methods*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media