title: Gastric cancer staging with dual energy spectral CT imaging.
abstract: OBJECTIVE
  To evaluate the clinical utility of dual energy spectral CT (DEsCT) in staging and characterizing gastric cancers.
  
  
  METHODS
  96 patients suspected of gastric cancers underwent dual-phasic scans (arterial phase (AP) and portal venous phase (PP)) with DEsCT mode. Three types of images were reconstructed for analysis: conventional polychromatic images, material-decomposition images, and monochromatic image sets with photon energies from 40 to 140 keV. The polychromatic and monochromatic images were compared in TNM staging. The iodine concentrations in the lesions and lymph nodes were measured on the iodine-based material-decomposition images. These values were further normalized against that in aorta and the normalized iodine concentration (nIC) values were statistically compared. Results were correlated with pathological findings.
  
  
  RESULTS
  The overall accuracies for T, N and M staging were (81.2%, 80.0%, and 98.9%) and (73.9%, 75.0%, and 98.9%) determined with the monochromatic images and the conventional kVp images, respectively. The improvement of the accuracy in N-staging using the keV images was statistically significant (p<0.05). The nIC values between the differentiated and undifferentiated carcinoma and between metastatic and non-metastatic lymph nodes were significantly different both in AP (p = 0.02, respectively) and PP (p = 0.01, respectively). Among metastatic lymph nodes, nIC of the signet-ring cell carcinoma were significantly different from the adenocarcinoma (p = 0.02) and mucinous adenocarcinoma (p = 0.01) in PP.
  
  
  CONCLUSIONS
  The monochromatic images obtained with DEsCT may be used to improve the N-staging accuracy. Quantitative iodine concentration measurements may be helpful for differentiating between differentiated and undifferentiated gastric carcinoma, and between metastatic and non-metastatic lymph nodes.
authors: Department of Radiology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors: Zilai
authors: Z
authors: Pan
authors: Lifang
authors: L
authors: Pang
authors: Bei
authors: B
authors: Ding
authors: Chao
authors: C
authors: Yan
authors: Huan
authors: H
authors: Zhang
authors: Lianjun
authors: L
authors: Du
authors: Baisong
authors: B
authors: Wang
authors: Qi
authors: Q
authors: Song
authors: Kemin
authors: K
authors: Chen
authors: Fuhua
authors: F
authors: Yan
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007455:Iodine / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods*; D015900:Radiography, Dual-Energy Scanned Projection / Q000379:methods*; D013274:Stomach Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology*
chemical_list: D007455:Iodine