title: Simultaneous reduction in noise and cross-contamination artifacts for dual-energy X-ray CT.
abstract: OBJECTIVE
  Dual-energy CT imaging tends to suffer from much lower signal-to-noise ratio than single-energy CT. In this paper, we propose an improved anticorrelated noise reduction (ACNR) method without causing cross-contamination artifacts.
  
  
  METHODS
  The proposed algorithm diffuses both basis material density images (e.g., water and iodine) at the same time using a novel correlated diffusion algorithm. The algorithm has been compared to the original ACNR algorithm in a contrast-enhanced, IRB-approved patient study. Material density accuracy and noise reduction are quantitatively evaluated by the percent density error and the percent noise reduction.
  
  
  RESULTS
  Both algorithms have significantly reduced the noises of basis material density images in all cases. The average percent noise reduction is 69.3% and 66.5% with the ACNR algorithm and the proposed algorithm, respectively. However, the ACNR algorithm alters the original material density by an average of 13% (or 2.18 mg/cc) with a maximum of 58.7% (or 8.97 mg/cc) in this study. This is evident in the water density images as massive cross-contaminations are seen in all five clinical cases. On the contrary, the proposed algorithm only changes the mean density by 2.4% (or 0.69 mg/cc) with a maximum of 7.6% (or 1.31 mg/cc). The cross-contamination artifacts are significantly minimized or absent with the proposed algorithm.
  
  
  CONCLUSIONS
  The proposed algorithm can significantly reduce image noise present in basis material density images from dual-energy CT imaging, with minimized cross-contaminations compared to the ACNR algorithm.
authors.affiliation: Department of Radiology, Boston University Medical Center, Boston, MA 02118, USA. bhli@mail.xjtu.edu.cn
authors.forename: Baojun
authors.initials: B
authors.lastname: Li
authors.forename: Baohong
authors.initials: B
authors.lastname: Li
authors.forename: Jack
authors.initials: J
authors.lastname: Luo
authors.forename: Peng
authors.initials: P
authors.lastname: Tang
authors.forename: Jiandong
authors.initials: J
authors.lastname: Mao
authors.forename: Xiaoye
authors.initials: X
authors.lastname: Wu
mesh_terms: D000465:Algorithms; D016477:Artifacts; D006801:Humans; D011856:Radiographic Image Enhancement; D011860:Radiography, Abdominal; D059629:Signal-To-Noise Ratio; D014057:Tomography, X-Ray Computed