title: Gastric Carcinoma: Ex Vivo MR Imaging at 7.0 T-Correlation with Histopathologic Findings.
abstract: OBJECTIVE
  To determine the imaging detail and diagnostic information that can be obtained at 7.0-T magnetic resonance (MR) imaging with a voxel volume of 9.5-14.0 nL as a means of evaluating the depth of mural invasion by gastric carcinomas ex vivo.
  
  
  METHODS
  This study was approved by the institutional review board, and written informed consent was obtained from each patient. Twenty gastric specimens containing 20 carcinomas were studied with a 7.0-T MR imaging system equipped with a four-channel surface coil. MR images were obtained with a 50-60 × 25-30 mm field of view, a 512 × 256 matrix, and a 1.0-mm section thickness, resulting in a voxel volume of 0.0095-0.0140 mm(3) (9.5-14.0 nL). The signal intensity of the gastric wall layers, tumor tissue, and fibrosis was described as low, intermediate, or high by comparing it with the signal intensity of the muscularis propria. Depth of invasion initially was assessed by two reviewers independently and then by the two reviewers in consensus. MR images were compared with histopathologic findings.
  
  
  RESULTS
  The 7.0-T T2-weighted MR images clearly depicted the normal gastric wall in all 20 specimens (100%) as consisting of seven layers, which clearly corresponded to the tissue layers of the gastric wall. These MR images enabled clear differentiation between tumor tissue and fibrosis. Reviewers disagreed on the depth of invasion at the initial reading in three (15%) of 20 specimens (between mucosa and submucosa in two specimens and between muscularis propria and subserosa and serosa in one specimen); however, in all 20 gastric carcinomas, the depth of invasion could be accurately determined on T2-weighted images after consensus interpretation.
  
  
  CONCLUSIONS
  Ex vivo 7.0-T MR imaging enables clear delineation of the gastric wall layers and clear differentiation of tumor tissue from fibrosis and allows one to assess the depth of mural invasion by gastric carcinomas.
authors.affiliation: From the Departments of Diagnostic Radiology and Oncology (I.Y.), Pediatrics, Perinatal and Maternal Medicine (N.M.), Gastric Surgery (K. Kato, K. Kojima), Esophageal Surgery (T.K.), and Pathology (E.I., D.K., Y.E.), Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan; Department of Physiology, Keio University School of Medicine, Tokyo, Japan (K.H., H.O.); and Central Institute for Experimental Animals, Kawasaki, Japan (K.H.).
authors.forename: Ichiro
authors.initials: I
authors.lastname: Yamada
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Miyasaka
authors.forename: Keigo
authors.initials: K
authors.lastname: Hikishima
authors.forename: Keiji
authors.initials: K
authors.lastname: Kato
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Kojima
authors.forename: Tatsuyuki
authors.initials: T
authors.lastname: Kawano
authors.forename: Eisaku
authors.initials: E
authors.lastname: Ito
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kobayashi
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Eishi
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Okano
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D013274:Stomach Neoplasms / Q000473:pathology* / Q000601:surgery