title: Iterative reconstruction reduces abdominal CT dose.
abstract: OBJECTIVE
  In medical imaging, lowering radiation dose from computed tomography scanning, without reducing diagnostic performance is a desired achievement. Iterative image reconstruction may be one tool to achieve dose reduction. This study reports the diagnostic performance using a blending of 50% statistical iterative reconstruction (ASIR) and filtered back projection reconstruction (FBP) compared to standard FBP image reconstruction at different dose levels for liver phantom examinations.
  
  
  METHODS
  An anthropomorphic liver phantom was scanned at 250, 185, 155, 140, 120 and 100 mAs, on a 64-slice GE Lightspeed VCT scanner. All scans were reconstructed with ASIR and FBP. Four readers evaluated independently on a 5-point scale 21 images, each containing 32 test sectors. In total 672 areas were assessed. ROC analysis was used to evaluate the differences.
  
  
  RESULTS
  There was a difference in AUC between the 250 mAs FBP images and the 120 and 100 mAs FBP images. ASIR reconstruction gave a significantly higher diagnostic performance compared to standard reconstruction at 100 mAs.
  
  
  CONCLUSIONS
  A blending of 50-90% ASIR and FBP may improve image quality of low dose CT examinations of the liver, and thus give a potential for reducing radiation dose.
authors.affiliation: The Intervention Centre, Oslo University Hospital, Rikshospitalet, Postboks 4950 Nydalen, N-0424 Oslo, Norway. anne.catrine.martinsem@ous-hf.no
authors.forename: Anne Catrine Trægde
authors.initials: AC
authors.lastname: Martinsen
authors.forename: Hilde Kjernlie
authors.initials: HK
authors.lastname: Sæther
authors.forename: Per Kristian
authors.initials: PK
authors.lastname: Hol
authors.forename: Dag Rune
authors.initials: DR
authors.lastname: Olsen
authors.forename: Per
authors.initials: P
authors.lastname: Skaane
mesh_terms: D000465:Algorithms; D019540:Area Under Curve; D006801:Humans; D008099:Liver / Q000000981:diagnostic imaging*; D019047:Phantoms, Imaging; D012372:ROC Curve; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted; D011860:Radiography, Abdominal / Q000379:methods*; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*