title: Coronary computed tomography angiography with model-based iterative reconstruction using a radiation exposure similar to chest X-ray examination.
abstract: OBJECTIVE
  To evaluate the feasibility and image quality of coronary computed tomography angiography (CCTA) acquisition with a submillisievert fraction of effective radiation dose using model-based iterative reconstruction (MBIR) for noise reduction.
  
  
  RESULTS
  In 42 patients undergoing standard low-dose (100-120 kV; 450-700 mA) and additional ultra-low-dose CCTA (80-100 kV; 150-210 mA) reconstructed with MBIR, segmental image quality was graded on a four-point scale [(i): non-evaluative, (ii): good, (iii): adequate, and (iv): excellent]. Signal-to-noise ratio (SNR) was calculated dividing left main artery (LMA) and right coronary artery (RCA) attenuation by the aortic root noise. Over a wide range of body mass index (18-40 kg/m(2)), the estimated median radiation dose exposure was 1.19 mSv [interquartile range (IQR): 1.07-1.30 mSv] for standard and 0.21 mSv (IQR: 0.18-0.23 mSv) for ultra-low-dose CCTA (P < 0.001). The median image quality score per segment was 3.5 (IQR: 3.0-4.0) in standard CCTA vs. 3.5 (IQR: 2.5-4.0) in ultra-low dose with MBIR (P = 0.29). Diagnostic image quality (scores 2-4) was found in 98.7 vs. 97.8% coronary segments (P = 0.36). Introduction of MBIR for ultra-low-dose CCTA resulted in a significant increase in SNR (P < 0.001) for LMA (from 15 ± 5 to 29 ± 7) and RCA (from 14 ± 4 to 27 ± 6) despite 82% dose reduction.
  
  
  CONCLUSIONS
  Coronary computed tomography angiography acquisition with diagnostic image quality is feasible at an ultra-low radiation dose of 0.21 mSv, e.g. in the range reported for a postero-anterior and lateral chest X-ray.
authors.affiliation: Division of Nuclear Medicine and Cardiac Imaging, University Hospital Zurich, Ramistrasse 100, NUK C 42, CH-8091 Zurich, Switzerland.
authors.forename: Tobias A
authors.initials: TA
authors.lastname: Fuchs
authors.forename: Julia
authors.initials: J
authors.lastname: Stehli
authors.forename: Sacha
authors.initials: S
authors.lastname: Bull
authors.forename: Svetlana
authors.initials: S
authors.lastname: Dougoud
authors.forename: Olivier F
authors.initials: OF
authors.lastname: Clerc
authors.forename: Bernhard A
authors.initials: BA
authors.lastname: Herzog
authors.forename: Ronny R
authors.initials: RR
authors.lastname: Buechel
authors.forename: Oliver
authors.initials: O
authors.lastname: Gaemperli
authors.forename: Philipp A
authors.initials: PA
authors.lastname: Kaufmann
mesh_terms: D000328:Adult; D000368:Aged; D015992:Body Mass Index; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D033162:Incidental Findings; D008297:Male; D008875:Middle Aged; D011829:Radiation Dosage; D059629:Signal-To-Noise Ratio; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: Feasibility; Model-based iterative reconstruction; Ultra-low-dose coronary computed tomography angiography