title: Impact of reduced-radiation dual-energy protocols using 320-detector row computed tomography for analyzing urinary calculus components: initial in vitro evaluation.
abstract: OBJECTIVE
  To evaluate the impact of reduced-radiation dual-energy (DE) protocols using 320-detector row computed tomography on the differentiation of urinary calculus components.
  
  
  METHODS
  A total of 58 urinary calculi were placed into the same phantom and underwent DE scanning with 320-detector row computed tomography. Each calculus was scanned 4 times with the DE protocols using 135 kV and 80 kV tube voltage and different tube current combinations, including 100 mA and 570 mA (group A), 50 mA and 290 mA (group B), 30 mA and 170 mA (group C), and 10 mA and 60 mA (group D). The acquisition data of all 4 groups were then analyzed by stone DE analysis software, and the results were compared with x-ray diffraction analysis. Noise, contrast-to-noise ratio, and radiation dose were compared.
  
  
  RESULTS
  Calculi were correctly identified in 56 of 58 stones (96.6%) using group A and B protocols. However, only 35 stones (60.3%) and 16 stones (27.6%) were correctly diagnosed using group C and D protocols, respectively. Mean noise increased significantly and mean contrast-to-noise ratio decreased significantly from groups A to D (P <.05). In addition, the effective dose decreased markedly from groups A to D at 3.78, 1.81, 1.07, and 0.37 mSv, respectively.
  
  
  CONCLUSIONS
  Decreasing the DE tube currents from 100 mA and 570 mA to 50 mA and 290 mA resulted in 96.6% accuracy for urinary calculus component analysis while reducing patient radiation exposure to 1.81 mSv. Further reduction of tube currents may compromise diagnostic accuracy.
authors.affiliation: Medical Imaging Center, First Affiliated Hospital, Jinan University, Guangzhou, China. Electronic address: caixran@163.com.
authors.forename: Xiangran
authors.initials: X
authors.lastname: Cai
authors.affiliation: Department of Urology, Nanhua Affiliated Hospital, Nanhua University, Hengyang, China.
authors.forename: Qingchun
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: Medical Imaging Center, First Affiliated Hospital, Jinan University, Guangzhou, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Yu
authors.affiliation: Medical Imaging Center, First Affiliated Hospital, Jinan University, Guangzhou, China.
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Xian
authors.affiliation: Medical Imaging Center, First Affiliated Hospital, Jinan University, Guangzhou, China.
authors.forename: Youzhen
authors.initials: Y
authors.lastname: Feng
authors.affiliation: Medical Imaging Center, First Affiliated Hospital, Jinan University, Guangzhou, China.
authors.forename: Wencai
authors.initials: W
authors.lastname: Yang
authors.affiliation: Medical Imaging Center, First Affiliated Hospital, Jinan University, Guangzhou, China.
authors.forename: Xukai
authors.initials: X
authors.lastname: Mo
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D006801:Humans; D066298:In Vitro Techniques; D008875:Middle Aged; D011446:Prospective Studies; D011829:Radiation Dosage; D014057:Tomography, X-Ray Computed / Q000379:methods; D014545:Urinary Calculi / Q000737:chemistry* / Q000000981:diagnostic imaging*; D055815:Young Adult