title: Detection of gallbladder stones by dual-energy spectral computed tomography imaging.
abstract: OBJECTIVE
  To evaluate the detectability of gallbladder stones by dual-energy spectral computed tomography (CT) imaging.
  
  
  METHODS
  Totally 217 patients with surgically confirmed gallbladder stones were retrospectively analyzed who underwent single-source dual-energy CT scanning from August 2011 to December 2013. Polychromatic images were acquired. And post-processing software was used to reconstruct monochromatic (40 keV and 140 keV) images, and calcium-lipid pair-wise base substance was selected to acquire calcium base images and lipid base images. The above 5 groups of images were evaluated by two radiologists separately with 10-year experience in CT image reading. In the 5 groups of images, the cases in the positive group and negative group were counted and then the detection rate was calculated. The inter-observer agreement on the scoring results was analyzed by Kappa test, and the scoring results were analyzed by Wilcoxon test, with P < 0.05 indicating that the difference was statistically significant. The stone detection results of the 5 groups of images were analyzed by χ(2) test.
  
  
  RESULTS
  There was good inter-observer agreement (κ = 0.772). In 217 patients with gallbladder stones, there was a statistically significant difference in stone visualization between spectral images (40 keV, 140 keV, calcium base and lipid base images) and polychromatic images (P < 0.05). 40 keV monochromatic images were better than 140 keV monochromatic images (4.90 ± 0.35 vs 4.53 ± 1.15, P < 0.05), and calcium base images were superior to lipid base images (4.91 ± 0.43 vs 4.77 ± 0.63, P < 0.05), but there was no statistically significant difference between 40 keV monochromatic images and calcium base images (4.90 ± 0.35 vs 4.91 ± 0.43, P > 0.05). In 217 gallbladder stone patients, there were 21, 3, 28, 5 and 12 negative stone cases in polychromatic images, 40 keV images, 140 keV images, calcium base images and lipid base images, respectively, and the differences among the five groups were statistically significant (P < 0.05).
  
  
  CONCLUSIONS
  Monochromatic images and base substance images have a good clinical prospect in the iso-density stone detection.
authors.affiliation: An-Liang Chen, Ai-Lian Liu, Sheng Wang, Jing-Hong Liu, Ye Ju, Mei-Yu Sun, Yi-Jun Liu, Department of Radiology, The First Affiliated Hospital of Dalian Medical University, Dalian 116011, Liaoning Province, China.
authors.forename: An-Liang
authors.initials: AL
authors.lastname: Chen
authors.affiliation: An-Liang Chen, Ai-Lian Liu, Sheng Wang, Jing-Hong Liu, Ye Ju, Mei-Yu Sun, Yi-Jun Liu, Department of Radiology, The First Affiliated Hospital of Dalian Medical University, Dalian 116011, Liaoning Province, China.
authors.forename: Ai-Lian
authors.initials: AL
authors.lastname: Liu
authors.affiliation: An-Liang Chen, Ai-Lian Liu, Sheng Wang, Jing-Hong Liu, Ye Ju, Mei-Yu Sun, Yi-Jun Liu, Department of Radiology, The First Affiliated Hospital of Dalian Medical University, Dalian 116011, Liaoning Province, China.
authors.forename: Sheng
authors.initials: S
authors.lastname: Wang
authors.affiliation: An-Liang Chen, Ai-Lian Liu, Sheng Wang, Jing-Hong Liu, Ye Ju, Mei-Yu Sun, Yi-Jun Liu, Department of Radiology, The First Affiliated Hospital of Dalian Medical University, Dalian 116011, Liaoning Province, China.
authors.forename: Jing-Hong
authors.initials: JH
authors.lastname: Liu
authors.affiliation: An-Liang Chen, Ai-Lian Liu, Sheng Wang, Jing-Hong Liu, Ye Ju, Mei-Yu Sun, Yi-Jun Liu, Department of Radiology, The First Affiliated Hospital of Dalian Medical University, Dalian 116011, Liaoning Province, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Ju
authors.affiliation: An-Liang Chen, Ai-Lian Liu, Sheng Wang, Jing-Hong Liu, Ye Ju, Mei-Yu Sun, Yi-Jun Liu, Department of Radiology, The First Affiliated Hospital of Dalian Medical University, Dalian 116011, Liaoning Province, China.
authors.forename: Mei-Yu
authors.initials: MY
authors.lastname: Sun
authors.affiliation: An-Liang Chen, Ai-Lian Liu, Sheng Wang, Jing-Hong Liu, Ye Ju, Mei-Yu Sun, Yi-Jun Liu, Department of Radiology, The First Affiliated Hospital of Dalian Medical University, Dalian 116011, Liaoning Province, China.
authors.forename: Yi-Jun
authors.initials: YJ
authors.lastname: Liu
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016009:Chi-Square Distribution; D002648:Child; D005260:Female; D042882:Gallstones / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D011857:Radiographic Image Interpretation, Computer-Assisted; D015203:Reproducibility of Results; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult
keywords: Computed tomography; Gallbladder stone; Spectral imaging