title: Evaluating the response of gastric carcinomas to neoadjuvant chemotherapy using iodine concentration on spectral CT: a comparison with pathological regression.
abstract: OBJECTIVE
  To investigate the potential of iodine concentration (IC) determined using virtual monochromatic spectral computed tomography (CT) to predict the response of gastric carcinomas to preoperative neoadjuvant chemotherapy (NC).
  
  
  METHODS
  A total of 20 patients were enrolled who underwent two spectral CT examinations (1 week before and two cycles after NC). The percentage change in tumour thickness (%ΔCWT) and in IC on the arterial phase (%ΔIC-a) and venous phase (%ΔIC-v) after NC were calculated and compared for different histopathological regression grades and response groups. The diagnostic efficacies to discriminate good response (GR) and poor response (PR) of the above three parameters were evaluated using receiver operating characteristic (ROC) curves.
  
  
  RESULTS
  The decrease rate of %ΔIC-a for the GR group was higher than that for the PR group (-0.59 [-0.76, -0.20] versus -0.11 [-0.75, 0.92], p=0.012). There was no significant difference in the %ΔIC-v and %ΔCWT values between the GR and PR groups (p=0.076 and p=0.779, respectively). The areas under the ROC curve (AUC) values were 0.857, 0.762, and 0.542 for %ΔIC-a, %ΔIC-v, and %ΔCWT, respectively, in the response prediction. The cut-off value for identifying PR was a decrease rate of <52.9% for %ΔIC-a, and the sensitivity and specificity values were 0.857 and 0.833.
  
  
  CONCLUSIONS
  Changes in the IC for gastric carcinomas following NC were detected using spectral CT and correlated with histopathological regression. The prediction efficacy for IC was better than that for tumour thickness, with IC on the arterial phase being a better predictor than IC on the venous phase.
authors.affiliation: Department of Radiology, Peking University Cancer Hospital & Institute, Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), Beijing 100142, China.
authors.forename: L
authors.initials: L
authors.lastname: Tang
authors.affiliation: Department of Gastrointestinal Surgery, Peking University Cancer Hospital & Institute, Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), Beijing 100142, China.
authors.forename: Z-Y
authors.initials: ZY
authors.lastname: Li
authors.affiliation: Department of Pathology, Peking University Cancer Hospital & Institute, Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), Beijing 100142, China.
authors.forename: Z-W
authors.initials: ZW
authors.lastname: Li
authors.affiliation: Department of Radiology, Peking University Cancer Hospital & Institute, Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), Beijing 100142, China.
authors.forename: X-P
authors.initials: XP
authors.lastname: Zhang
authors.affiliation: Department of Radiology, Peking University Cancer Hospital & Institute, Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), Beijing 100142, China.
authors.forename: Y-L
authors.initials: YL
authors.lastname: Li
authors.affiliation: Department of Radiology, Peking University Cancer Hospital & Institute, Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), Beijing 100142, China.
authors.forename: X-T
authors.initials: XT
authors.lastname: Li
authors.affiliation: Department of Radiology, Peking University Cancer Hospital & Institute, Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), Beijing 100142, China.
authors.forename: Z-L
authors.initials: ZL
authors.lastname: Wang
authors.affiliation: Department of Gastrointestinal Surgery, Peking University Cancer Hospital & Institute, Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), Beijing 100142, China. Electronic address: jiafuj@hotmail.com.
authors.forename: J-F
authors.initials: JF
authors.lastname: Ji
authors.affiliation: Department of Radiology, Peking University Cancer Hospital & Institute, Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), Beijing 100142, China. Electronic address: sunysabc@163.com.
authors.forename: Y-S
authors.initials: YS
authors.lastname: Sun
mesh_terms: D000328:Adult; D000368:Aged; D017024:Chemotherapy, Adjuvant; D003287:Contrast Media / Q000493:pharmacokinetics; D005260:Female; D006801:Humans; D007455:Iodine / Q000493:pharmacokinetics; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D019047:Phantoms, Imaging; D012372:ROC Curve; D013274:Stomach Neoplasms / Q000000981:diagnostic imaging / Q000188:drug therapy*; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media; D007455:Iodine