title: Head-to-head comparison of adaptive statistical and model-based iterative reconstruction algorithms for submillisievert coronary CT angiography.
abstract: Iterative reconstruction (IR) algorithms allow for a significant reduction in radiation dose of coronary computed tomography angiography (CCTA). We performed a head-to-head comparison of adaptive statistical IR (ASiR) and model-based IR (MBIR) algorithms to assess their impact on quantitative image parameters and diagnostic accuracy for submillisievert CCTA.
  
  
  
  CCTA datasets of 91 patients were reconstructed using filtered back projection (FBP), increasing contributions of ASiR (20, 40, 60, 80, and 100%), and MBIR. Signal and noise were measured in the aortic root to calculate signal-to-noise ratio (SNR). In a subgroup of 36 patients, diagnostic accuracy of ASiR 40%, ASiR 100%, and MBIR for diagnosis of coronary artery disease (CAD) was compared with invasive coronary angiography. Median radiation dose was 0.21 mSv for CCTA. While increasing levels of ASiR gradually reduced image noise compared with FBP (up to - 48%, P < 0.001), MBIR provided largest noise reduction (-79% compared with FBP) outperforming ASiR (-59% compared with ASiR 100%; P < 0.001). Increased noise and lower SNR with ASiR 40% and ASiR 100% resulted in substantially lower diagnostic accuracy to detect CAD as diagnosed by invasive coronary angiography compared with MBIR: sensitivity and specificity were 100 and 37%, 100 and 57%, and 100 and 74% for ASiR 40%, ASiR 100%, and MBIR, respectively.
  
  
  
  MBIR offers substantial noise reduction with increased SNR, paving the way for implementation of submillisievert CCTA protocols in clinical routine. In contrast, inferior noise reduction by ASiR negatively affects diagnostic accuracy of submillisievert CCTA for CAD detection.
authors.affiliation: Department of Nuclear Medicine, Cardiac Imaging, University Hospital Zurich, Ramistrasse 100, CH-8091 Zurich, Switzerland.
authors.forename: Dominik C
authors.initials: DC
authors.lastname: Benz
authors.affiliation: Department of Nuclear Medicine, Cardiac Imaging, University Hospital Zurich, Ramistrasse 100, CH-8091 Zurich, Switzerland.
authors.forename: Tobias A
authors.initials: TA
authors.lastname: Fuchs
authors.affiliation: Department of Nuclear Medicine, Cardiac Imaging, University Hospital Zurich, Ramistrasse 100, CH-8091 Zurich, Switzerland.
authors.forename: Christoph
authors.initials: C
authors.lastname: Gräni
authors.affiliation: Department of Nuclear Medicine, Cardiac Imaging, University Hospital Zurich, Ramistrasse 100, CH-8091 Zurich, Switzerland.
authors.forename: Annina A
authors.initials: AA
authors.lastname: Studer Bruengger
authors.affiliation: Department of Nuclear Medicine, Cardiac Imaging, University Hospital Zurich, Ramistrasse 100, CH-8091 Zurich, Switzerland.
authors.forename: Olivier F
authors.initials: OF
authors.lastname: Clerc
authors.affiliation: Department of Nuclear Medicine, Cardiac Imaging, University Hospital Zurich, Ramistrasse 100, CH-8091 Zurich, Switzerland.
authors.forename: Fran
authors.initials: F
authors.lastname: Mikulicic
authors.affiliation: Department of Nuclear Medicine, Cardiac Imaging, University Hospital Zurich, Ramistrasse 100, CH-8091 Zurich, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Messerli
authors.affiliation: Department of Nuclear Medicine, Cardiac Imaging, University Hospital Zurich, Ramistrasse 100, CH-8091 Zurich, Switzerland.
authors.forename: Julia
authors.initials: J
authors.lastname: Stehli
authors.affiliation: Department of Nuclear Medicine, Cardiac Imaging, University Hospital Zurich, Ramistrasse 100, CH-8091 Zurich, Switzerland.
authors.forename: Mathias
authors.initials: M
authors.lastname: Possner
authors.affiliation: Department of Nuclear Medicine, Cardiac Imaging, University Hospital Zurich, Ramistrasse 100, CH-8091 Zurich, Switzerland.
authors.forename: Aju P
authors.initials: AP
authors.lastname: Pazhenkottil
authors.affiliation: Department of Nuclear Medicine, Cardiac Imaging, University Hospital Zurich, Ramistrasse 100, CH-8091 Zurich, Switzerland.
authors.forename: Oliver
authors.initials: O
authors.lastname: Gaemperli
authors.affiliation: Department of Nuclear Medicine, Cardiac Imaging, University Hospital Zurich, Ramistrasse 100, CH-8091 Zurich, Switzerland.
authors.forename: Philipp A
authors.initials: PA
authors.lastname: Kaufmann
authors.affiliation: Department of Nuclear Medicine, Cardiac Imaging, University Hospital Zurich, Ramistrasse 100, CH-8091 Zurich, Switzerland.
authors.forename: Ronny R
authors.initials: RR
authors.lastname: Buechel
mesh_terms: D000704:Analysis of Variance; D015331:Cohort Studies; D000072226:Computed Tomography Angiography / Q000379:methods*; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology; D016208:Databases, Factual; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D059629:Signal-To-Noise Ratio
keywords: adaptive statistical iterative reconstruction; model-based iterative reconstruction; submillisievert coronary CT angiography