title: Coronary CT angiography: comparison of a novel iterative reconstruction with filtered back projection for reconstruction of low-dose CT-Initial experience.
abstract: OBJECTIVE
  To prospectively compare subjective and objective image quality in 20% tube current coronary CT angiography (cCTA) datasets between an iterative reconstruction algorithm (SAFIRE) and traditional filtered back projection (FBP).
  
  
  METHODS
  Twenty patients underwent a prospectively ECG-triggered dual-step cCTA protocol using 2nd generation dual-source CT (DSCT). CT raw data was reconstructed using standard FBP at full-dose (Group_1a) and 80% tube current reduced low-dose (Group_1b). The low-dose raw data was additionally reconstructed using iterative raw data reconstruction (Group_2). Attenuation and image noise were measured in three regions of interest and signal-to-noise-ratio (SNR) as well as contrast-to-noise-ratio (CNR) was calculated. Subjective diagnostic image quality was evaluated using a 4-point Likert scale.
  
  
  RESULTS
  Mean image noise of group_2 was lowered by 22% on average when compared to group_1b (p<0.0001-0.0033), while there were no significant differences in mean attenuation within the same anatomical regions. The lower image noise resulted in significantly higher SNR and CNR ratios in group_2 compared to group_1b (p<0.0001-0.0232). Subjective image quality of group_2 (1.88 ± 0.63) was also rated significantly higher when compared to group_1b (1.58 ± 0.63, p=0.004).
  
  
  CONCLUSIONS
  Image quality of 80% tube current reduced iteratively reconstructed cCTA raw data is significantly improved when compared to standard FBP and consequently may improve the diagnostic accuracy of cCTA.
authors.affiliation: Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC 29401, USA.
authors.forename: Richard A P
authors.initials: RA
authors.lastname: Takx
authors.forename: U Joseph
authors.initials: UJ
authors.lastname: Schoepf
authors.forename: Antonio
authors.initials: A
authors.lastname: Moscariello
authors.forename: Marco
authors.initials: M
authors.lastname: Das
authors.forename: Garrett
authors.initials: G
authors.lastname: Rowe
authors.forename: Stefan O
authors.initials: SO
authors.lastname: Schoenberg
authors.forename: Christian
authors.initials: C
authors.lastname: Fink
authors.forename: Thomas
authors.initials: T
authors.lastname: Henzler
mesh_terms: D000465:Algorithms; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011829:Radiation Dosage; D011835:Radiation Protection / Q000379:methods; D011856:Radiographic Image Enhancement / Q000379:methods*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*