title: Image quality of ultra-low radiation exposure coronary CT angiography with an effective dose <0.1 mSv using high-pitch spiral acquisition and raw data-based iterative reconstruction.
abstract: OBJECTIVE
  We evaluated the potential of prospectively ECG-triggered high-pitch spiral acquisition with low tube voltage and current in combination with iterative reconstruction to achieve coronary CT angiography with sufficient image quality at an effective dose below 0.1 mSv.
  
  
  METHODS
  Contrast-enhanced coronary dual source CT angiography (2 × 128 × 0.6 mm, 80 kV, 50 mAs) in prospectively ECG-triggered high-pitch spiral acquisition mode was performed in 21 consecutive individuals (body weight <100 kg, heart rate ≤60/min). Images were reconstructed with raw data-based filtered back projection (FBP) and iterative reconstruction (IR). Image quality was assessed on a 4-point scale (1 = no artefacts, 4 = unevaluable).
  
  
  RESULTS
  Mean effective dose was 0.06 ± 0.01 mSv. Image noise was significantly reduced in IR (128.9 ± 46.6 vs. 158.2 ± 44.7 HU). The mean image quality score was lower for IR (1.9 ± 1.1 vs. 2.2 ± 1.0, P < 0.0001). Of 292 coronary segments, 55 in FBP and 40 in IR (P = 0.12) were graded "unevaluable". In patients with a body weight ≤75 kg, both in FBP and in IR, the rates of fully evaluable segments were significantly higher in comparison to patients >75 kg.
  
  
  CONCLUSIONS
  Coronary CT angiography with an estimated effective dose <0.1 mSv may provide sufficient image quality in selected patients through the combination of high-pitch spiral acquisition and raw data-based iterative reconstruction.
authors.affiliation: Department of Cardiology, University of Gießen, Klinikstr. 33, 35392 Gießen, Germany. annika.schuhbaeck@hotmail.de
authors.forename: Annika
authors.initials: A
authors.lastname: Schuhbaeck
authors.forename: Stephan
authors.initials: S
authors.lastname: Achenbach
authors.forename: Christian
authors.initials: C
authors.lastname: Layritz
authors.forename: Jasmin
authors.initials: J
authors.lastname: Eisentopf
authors.forename: Franziska
authors.initials: F
authors.lastname: Hecker
authors.forename: Tobias
authors.initials: T
authors.lastname: Pflederer
authors.forename: Soeren
authors.initials: S
authors.lastname: Gauss
authors.forename: Johannes
authors.initials: J
authors.lastname: Rixe
authors.forename: Willi
authors.initials: W
authors.lastname: Kalender
authors.forename: Werner G
authors.initials: WG
authors.lastname: Daniel
authors.forename: Michael
authors.initials: M
authors.lastname: Lell
authors.forename: Dieter
authors.initials: D
authors.lastname: Ropers
mesh_terms: D000465:Algorithms; D017023:Coronary Angiography / Q000379:methods*; D023921:Coronary Stenosis / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; 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; D036542:Tomography, Spiral Computed / Q000379:methods*