title: Adaptive Statistical Iterative Reconstruction-V: Impact on Image Quality in Ultralow-Dose Coronary Computed Tomography Angiography.
abstract: OBJECTIVE
  The clinical utility of a latest generation iterative reconstruction algorithm (adaptive statistical iterative reconstruction [ASiR-V]) has yet to be elucidated for coronary computed tomography angiography (CCTA). This study evaluates the impact of ASiR-V on signal, noise and image quality in CCTA.
  
  
  METHODS
  Sixty-five patients underwent clinically indicated CCTA on a 256-slice CT scanner using an ultralow-dose protocol. Data sets from each patient were reconstructed at 6 different levels of ASiR-V. Signal intensity was measured by placing a region of interest in the aortic root, LMA, and RCA. Similarly, noise was measured in the aortic root. Image quality was visually assessed by 2 readers.
  
  
  RESULTS
  Median radiation dose was 0.49 mSv. Image noise decreased with increasing levels of ASiR-V resulting in a significant increase in signal-to-noise ratio in the RCA and LMA (P < 0.001). Correspondingly, image quality significantly increased with higher levels of ASiR-V (P < 0.001).
  
  
  CONCLUSIONS
  ASiR-V yields substantial noise reduction and improved image quality enabling introduction of ultralow-dose CCTA.
authors: From the Department of Nuclear Medicine, Cardiac Imaging, University Hospital Zurich, Ramistrasse, Zurich, Switzerland.
authors: Dominik C
authors: DC
authors: Benz
authors: Christoph
authors: C
authors: Gräni
authors: Fran
authors: F
authors: Mikulicic
authors: Jan
authors: J
authors: Vontobel
authors: Tobias A
authors: TA
authors: Fuchs
authors: Mathias
authors: M
authors: Possner
authors: Olivier F
authors: OF
authors: Clerc
authors: Julia
authors: J
authors: Stehli
authors: Oliver
authors: O
authors: Gaemperli
authors: Aju P
authors: AP
authors: Pazhenkottil
authors: Ronny R
authors: RR
authors: Buechel
authors: Philipp A
authors: PA
authors: Kaufmann
mesh_terms: D000465:Algorithms; D000072226:Computed Tomography Angiography / Q000379:methods*; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D003627:Data Interpretation, Statistical; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D000069079:Radiation Exposure / Q000032:analysis* / Q000517:prevention & control; 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