title: Diagnostic performance of 64-channel multidetector CT in the evaluation of gastric cancer: differentiation of mucosal cancer (T1a) from submucosal involvement (T1b and T2).
abstract: OBJECTIVE
  To identify the computed tomographic (CT) findings in T1a and T1b cancers and to evaluate the diagnostic performance of multidetector CT with two-dimensional multiplanar reconstruction and three-dimensional CT gastrography for evaluating the preoperative staging of gastric cancer, with special emphasis on the differentiation between T1a and T1b cancers.
  
  
  METHODS
  The institutional review board approved this retrospective study. A total of 148 patients with gastric cancer (64 T1a, 36 T1b, and 48 T2) were included. To identify CT findings in T1a and T1b cancers, two radiologists in consensus interpreted the preoperative CT images of the 100 T1 cancers to determine the morphologic characteristics to be used as staging criteria on CT images. By using univariate and multiple logistic regression analyses, the diagnostic criteria to identify T1a and T1b cancers were developed. To evaluate the diagnostic performance of multidetector CT by using the criteria, two other blinded reviewers independently analyzed the CT images of all 148 patients to assess the T (classifying the depth of invasion as T1a, T1b, or T2) and N (classifying nodal involvement as absent or present) stage. CT staging was correlated with histopathologic results. Interobserver agreement was assessed by using weighted kappa statistics.
  
  
  RESULTS
  The detectability of T1b cancer was significantly higher than that of T1a cancer (P = .003). T1b cancer showed well-enhancing mucosal thickening more frequently than did T1a cancer (P = .002). By using the modified CT criteria, the overall accuracy values of T staging and N staging were 64.9% (96/148) and 79.1% (117/148) for reviewer 1 and 63.5% (94/148) and 83.8% (124/148) for reviewer 2, respectively. Weighted kappa values of T and N staging were 0.795 and 0.641, respectively.
  
  
  CONCLUSIONS
  On multidetector CT images, T1a cancer shows different imaging features than does T1b cancer regarding enhancing characteristics and detectability. Multidetector CT provides relatively valuable results of T and N staging, including differentiation between T1a, T1b, and T2 gastric cancers.
authors.affiliation: Department of Radiology, Seoul National University Hospital, 28 Yeongon-dong, Jongno-gu, Seoul 110-744, Korea.
authors.forename: In Joon
authors.initials: IJ
authors.lastname: Lee
authors.forename: Jeong Min
authors.initials: JM
authors.lastname: Lee
authors.forename: Seung Ho
authors.initials: SH
authors.lastname: Kim
authors.forename: Cheong-Ii
authors.initials: CI
authors.lastname: Shin
authors.forename: Jae Young
authors.initials: JY
authors.lastname: Lee
authors.forename: Se Hyung
authors.initials: SH
authors.lastname: Kim
authors.forename: Joon Koo
authors.initials: JK
authors.lastname: Han
authors.forename: Byung Ihn
authors.initials: BI
authors.lastname: Choi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016009:Chi-Square Distribution; D003287:Contrast Media; D005260:Female; D005753:Gastric Mucosa / Q000473:pathology; D005773:Gastroscopy; D006801:Humans; D021621:Imaging, Three-Dimensional; D007472:Iohexol / Q000031:analogs & derivatives; D016015:Logistic Models; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011857:Radiographic Image Interpretation, Computer-Assisted; D012189:Retrospective Studies; D013274:Stomach Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007472:Iohexol; C038192:iopromide