title: Spectral Imaging for Intracranial Stents and Stent Lumen.
abstract: BACKGROUND
  Application of computed tomography for monitoring intracranial stents is limited because of stent-related artifacts. Our purpose was to evaluate the effect of gemstone spectral imaging on the intracranial stent and stent lumen.
  
  
  METHODS
  In vitro, we scanned Enterprise stent phantom and a stent-cheese complex using the gemstone spectral imaging protocol. Follow-up gemstone spectral images of 15 consecutive patients with placement of Enterprise from January 2013 to September 2014 were also retrospectively reviewed. We used 70-keV, 140-keV, iodine (water), iodine (calcium), and iodine (hydroxyapatite) images to evaluate their effect on the intracranial stent and stent lumen. Two regions of interest were individually placed in stent lumen and adjacent brain tissue. Contrast-to-noise ratio was measured to determine image quality. The maximal diameter of stent markers was also measured to evaluate stent-related artifact. Two radiologists independently graded the visibility of the lumen at the maker location by using a 4-point scale. The mean of grading score, contrast/noise ratio and maximal diameter of stent markers were compared among all modes. All results were analyzed by SPSS version 20.
  
  
  RESULTS
  In vitro, iodine (water) images decreased metallic artifact of stent makers to the greatest degree. The most areas of cheese were observed on iodine (water) images. In vivo, iodine (water) images had the smallest average diameter of stent markers (0.33 ± 0.17mm; P < .05) and showed the highest mean grading score (2.94 ± 0.94; P < .05) and contrast/noise ratio of in-stent lumen (160.03 ±37.79; P < .05) among all the modes.
  
  
  CONCLUSIONS
  Iodine (water) images can help reduce stent-related artifacts of Enterprise and enhance contrast of in-stent lumen. Spectral imaging may be considered a noninvasive modality for following-up patients with in-stent stenosis.
authors.affiliation: Department of Radiology, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan.|Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
authors.forename: Chi-Lun
authors.initials: CL
authors.lastname: Weng
authors.affiliation: Department of Radiology, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan.|Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
authors.forename: Ying-Chi
authors.initials: YC
authors.lastname: Tseng
authors.affiliation: Department of Radiology, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan.|Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
authors.forename: David Yen-Ting
authors.initials: DY
authors.lastname: Chen
authors.affiliation: Department of Radiology, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan.|Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
authors.forename: Chi-Jen
authors.initials: CJ
authors.lastname: Chen
authors.affiliation: Department of Radiology, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan.|Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
authors.forename: Hui-Ling
authors.initials: HL
authors.lastname: Hsu
mesh_terms: D000368:Aged; D016477:Artifacts; D001921:Brain / Q000098:blood supply*; D003287:Contrast Media / Q000032:analysis; D017023:Coronary Angiography / Q000379:methods*; D005260:Female; D006801:Humans; D007455:Iodine / Q000032:analysis; D008297:Male; D008875:Middle Aged; D015607:Stents; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007455:Iodine