title: Gastric carcinoma: Evaluation with diffusion-tensor MR imaging and tractography ex vivo.
abstract: OBJECTIVE
  To determine the feasibility of diffusion-tensor imaging (DTI) and tractography as means of evaluating the depth of mural invasion by gastric carcinomas.
  
  
  METHODS
  This study was approved by our institutional review board, and written informed consent was obtained from each patient. Twenty gastric specimens containing a carcinoma were studied with a 7.0-T MR imaging system equipped with a four-channel phased-array surface coil. DTI was performed by using a field of view of 50-60 mm × 25-30 mm, matrix of 256 × 128, section thickness of 1mm, b value of 1000 s/mm2, and motion-probing gradients in seven noncollinear directions. The MR images were compared with the histopathologic findings as the reference standard.
  
  
  RESULTS
  In all 20 carcinomas (100%) the diffusion-weighted images, apparent diffusion coefficient (ADC) maps, fractional anisotropy (FA) maps, λ1 maps, and direction-encoded color FA maps made it possible to identify the same depth of tumor invasion of the gastric wall as observed during histopathologic examination. The λ1 maps provided the best contrast between the carcinomas and the layers of the gastric wall. The carcinomas also had lower ADC values and lower FA values than the normal gastric wall; thus, the carcinomas were clearly demarcated from the normal gastric wall. Tractography images were also useful for determining the depth of tumor invasion of the gastric wall.
  
  
  CONCLUSIONS
  DTI and tractography are feasible means of evaluating gastric specimens and provide excellent diagnostic accuracy for evaluating mural invasion by gastric carcinomas.
authors.affiliation: Department of Diagnostic Radiology and Nuclear Medicine, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan. Electronic address: yamada.crad@tmd.ac.jp.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Yamada
authors.affiliation: Department of Physiology, Keio University School of Medicine, Tokyo, Japan; Central Institute for Experimental Animals, Kanagawa, Japan.
authors.forename: Keigo
authors.initials: K
authors.lastname: Hikishima
authors.affiliation: Department of Pediatrics, Perinatal and Maternal Medicine, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Miyasaka
authors.affiliation: Department of Gastric Surgery, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Keiji
authors.initials: K
authors.lastname: Kato
authors.affiliation: Department of Gastric Surgery, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Kojima
authors.affiliation: Department of Esophageal Surgery, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Tatsuyuki
authors.initials: T
authors.lastname: Kawano
authors.affiliation: Department of Pathology, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Eisaku
authors.initials: E
authors.lastname: Ito
authors.affiliation: Department of Pathology, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kobayashi
authors.affiliation: Department of Pathology, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Eishi
authors.affiliation: Department of Physiology, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Okano
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods*; D009361:Neoplasm Invasiveness; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013274:Stomach Neoplasms / Q000473:pathology*
keywords: Diffusion-tensor imaging; Diffusion-tensor tractography; Diffusion-weighted imaging; Gastric carcinoma; MR imaging; Stomach