title: CT angiography of the kidney using routine CT and the latest Gemstone Spectral Imaging combination of different noise indexes: image quality and radiation dose.
abstract: OBJECTIVE
  The objective of our study was to compare the image quality and radiation dose of computed tomography angiography (CTA) of the kidney in patients with different body mass indexes using routine CT and the latest Gemstone Spectral Imaging (GSI) combination of different noise indexes (NI) with the adaptive statistical iterative reconstruction 2.0 algorithm (ASiR 2.0).
  
  
  METHODS
  A total of 120 patients who had undergone a CTA of the kidney were divided into four groups (A, B, C and D), with 30 patients in each group. Group A underwent a routine CT examination, while groups B, C and D underwent GSI with different noise indexes. All images were restructured using ASiR 2.0. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of all images were calculated when the kidney CTA was completed. Each subjective image evaluation used a 5-point scoring method and was conducted by two independent radiologists. The CT dose index of volume (CTDIvol) and dose-length product (DLP) were recorded, and the mean value was calculated. The DLP was converted to the effective dose (ED). All data were compared with one-way ANOVA.
  
  
  RESULTS
  The SNR, CNR and subjective image quality in group A were significantly lower than in groups B, C and D (P < 0.01). There were no significant differences in SNR, CNR and subjective image quality among groups B, C and D. The ED of group D decreased by 47.81 and 18.59% relative to groups A and B, respectively (P < 0.01).
  
  
  CONCLUSIONS
  The latest GSI with different NI values can more effectively reduce the radiation dose than can the routine CT scan mode for a kidney CTA while still maintaining diagnostic image quality.
authors.affiliation: Department of Radiology, The Affiliated Hospital of Hebei University, 212 Yuhua East Road, Baoding City, 071000, People's Republic of China. zyx_zyx999@163.com.
authors.forename: Yongxia
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Department of Radiology, The Affiliated Hospital of Hebei University, 212 Yuhua East Road, Baoding City, 071000, People's Republic of China.
authors.forename: Yanmin
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Department of Radiology, The Affiliated Hospital of Hebei University, 212 Yuhua East Road, Baoding City, 071000, People's Republic of China.
authors.forename: Ziwei
authors.initials: Z
authors.lastname: Zuo
authors.affiliation: Department of Radiology, The Affiliated Hospital of Hebei University, 212 Yuhua East Road, Baoding City, 071000, People's Republic of China.
authors.forename: Shujie
authors.initials: S
authors.lastname: Cheng
mesh_terms: D000465:Algorithms; D016477:Artifacts; D000072226:Computed Tomography Angiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted; D012077:Renal Artery / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: Adaptive statistical iterative reconstruction 2.0; CT angiography of the kidney; Gemstone Spectral Imaging; Image quality; Noise index; Radiation dose