title: Vessel Visibility Assessment of Low Tube Voltage Coronary Computed Tomography Angiography Determined with Contrast-to-Noise Ratio.
abstract: The purpose of this study was to investigate the association of vessel visibility and radiation dose using contrast-to-noise ratio (CNR) method with low tube voltage in coronary computed tomography angiography (c-CTA).
  
  
  
  We performed electrocardiogram-gated scan of 2.0-mm diameter simulated vessel in the center of the cardiac phantom by the use of a 64-detector CT scanner. Reference CNR was calculated from the target coronary CT number (CTnumberA; 350 Hounsfield units [HU]), epicardial fat CT number (CTnumberB; -100 HU), and target epicardial fat standard deviation (SD) number (SDB; 25 HU) at the 120 kV. We obtained the tube current at low tube voltage (100 and 80 kV) to perform the similar reference CNR at 120 kV. The full widths at half maximum from axial images were evaluated with quantitative evaluation and three types of visualizations of the vessel phantom were evaluated with the qualitative evaluations.
  
  
  
  CTnumberAof 100 and 80 kV were increased by 26% and 50%, respectively, compared with 120 kV (P<0.01). SDBwas also increased by a similar ratio (P<0.01). CTDIvolof 100 and 80 kV were decreased by 39% and 51%, respectively, compared with 120 kV (P<0.05). There were no significant voltage differences among three tubes in quantitative and qualitative evaluations at the same CNR (P> 0.05).
  
  
  
  In this phantom study, these results show that the CNR method with low tube voltage achieves radiation dose reduction without decreasing the image quality.
authors.affiliation: Department of Radiological Technology, Tsuchiya General Hospital.
authors.forename: Yoriaki
authors.initials: Y
authors.lastname: Matsumoto
authors.forename: Takanori
authors.initials: T
authors.lastname: Masuda
authors.forename: Yukari
authors.initials: Y
authors.lastname: Yamashita
authors.forename: Takayuki
authors.initials: T
authors.lastname: Oku
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Uyama
authors.forename: Tomoyasu
authors.initials: T
authors.lastname: Sato
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Imada
mesh_terms: D000072226:Computed Tomography Angiography / Q000379:methods*; D017023:Coronary Angiography / Q000379:methods*; D009622:Noise; D011829:Radiation Dosage