title: Impact of Adaptive Statistical Iterative Reconstruction (ASIR) on radiation dose and image quality in aortic dissection studies: a qualitative and quantitative analysis.
abstract: OBJECTIVE
  The purpose of the study was to quantify the radiation dose reduction achieved when imaging the aorta using Adaptive Statistical Iterative Reconstruction (ASIR) and to determine if this has an effect on image quality.
  
  
  METHODS
  We retrospectively reviewed 31 CT angiography examinations of the thoracic and abdominal aorta performed with ASIR and 32 consecutive similar examinations performed without ASIR. Volume CT dose index (CTDI(vol)), dose-length product (DLP), aortic enhancement at multiple levels, aorta-to-muscle contrast-to-noise ratio at multiple levels, and subjective image quality were compared between the two groups.
  
  
  RESULTS
  The mean CTDI(vol) and DLP were significantly lower for the studies performed with ASIR versus studies without ASIR (15.6 vs 21.5 mGy, with an average difference of 5.8 mGy [95% CI 2.3-9.4 mGy] and 818 vs 1075 mGy × cm with an average difference of -257 mGy × cm [54-460 mGy × cm], respectively). Aortic enhancement, aortic signal-to-noise ratio, and aortic to muscle contrast-to-noise ratio were not different between the two groups. Subjectively, one reviewer preferred the non-ASIR images and one found the images equivalent. Both reviewers believed the images were of diagnostic quality.
  
  
  CONCLUSIONS
  A 29% decrease in CTDI(vol) and a 20% decrease in DLP were obtained in scans with ASIR compared with scans without ASIR, without a quantitative loss of image quality.
authors.affiliation: Department of Diagnostic Imaging, Yale University School of Medicine, New Haven, CT 06520, USA. daniel.cornfeld@yale.edu
authors.forename: Daniel
authors.initials: D
authors.lastname: Cornfeld
authors.forename: Gary
authors.initials: G
authors.lastname: Israel
authors.forename: Ezra
authors.initials: E
authors.lastname: Detroy
authors.forename: Jamal
authors.initials: J
authors.lastname: Bokhari
authors.forename: Hamid
authors.initials: H
authors.lastname: Mojibian
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000784:Aortic Dissection / Q000000981:diagnostic imaging*; D000792:Angiography; D001014:Aortic Aneurysm / Q000000981:diagnostic imaging*; D003287:Contrast Media; D005260:Female; D006801:Humans; D007472:Iohexol; D008297:Male; D008875:Middle Aged; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media; D007472:Iohexol