title: Virtual non-contrast computer tomography (CT) with spectral CT as an alternative to conventional unenhanced CT in the assessment of gastric cancer.
abstract: OBJECTIVE
  The purpose of this study was to evaluate computed tomography (CT) virtual non-contrast (VNC) spectral imaging for gastric carcinoma.
  
  
  METHODS
  Fifty-two patients with histologically proven gastric carcinomas underwent gemstone spectral imaging (GSI) including non-contrast and contrast-enhanced hepatic arterial, portal venous, and equilibrium phase acquisitions prior to surgery. VNC arterial phase (VNCa), VNC venous phase (VNCv), and VNC equilibrium phase (VNCe) images were obtained by subtracting iodine from iodine/water images. Images were analyzed with respect to image quality, gastric carcinoma-intragastric water contrast-to-noise ratio (CNR), gastric carcinoma-perigastric fat CNR, serosal invasion, and enlarged lymph nodes around the lesions.
  
  
  RESULTS
  Carcinoma-water CNR values were significantly higher in VNCa, VNCv, and VNCe images than in normal CT images (2.72, 2.60, 2.61, respectively, vs 2.35, p≤0.008). Carcinoma- perigastric fat CNR values were significantly lower in VNCa, VNCv, and VNCe images than in normal CT images (7.63, 7.49, 7.32, respectively, vs 8.48, p<0.001). There were no significant differences of carcinoma-water CNR and carcinoma-perigastric fat CNR among VNCa, VNCv, and VNCe images. There was no difference in the determination of invasion or enlarged lymph nodes between normal CT and VNCa images.
  
  
  CONCLUSIONS
  VNC arterial phase images may be a surrogate for conventional non-contrast CT images in gastric carcinoma evaluation.
authors.affiliation: Department of Radiology, the First Affiliated Hospital of Dalian Medical University, Dalian, China E-mail : cjr.liuailian@vip.163.com.
authors.forename: Shi-Feng
authors.initials: SF
authors.lastname: Tian
authors.forename: Ai-Lian
authors.initials: AL
authors.lastname: Liu
authors.forename: He-Qing
authors.initials: HQ
authors.lastname: Wang
authors.forename: Jing-Hong
authors.initials: JH
authors.lastname: Liu
authors.forename: Mei-Yu
authors.initials: MY
authors.lastname: Sun
authors.forename: Yi-Jun
authors.initials: YJ
authors.lastname: Liu
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008198:Lymph Nodes / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D011856:Radiographic Image Enhancement / Q000379:methods*; D059629:Signal-To-Noise Ratio; D013274:Stomach Neoplasms / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media