title: Value of nonvisualized primary lesions of gastric cancer on preoperative MDCT.
abstract: OBJECTIVE
  The purpose of this study was to retrospectively determine the value of nonvisualized primary lesions on preoperative MDCT of patients with gastric cancer.
  
  
  METHODS
  The records of patients who had undergone radical gastrectomy for gastric cancer between August 2004 and August 2006 were retrospectively reviewed. Each patient was given 500-1,000 mL of water to drink, and 16-MDCT for preoperative staging was performed with i.v. contrast agents. Transverse and coronal reconstructed images had been prospectively interpreted as a part of daily practice. TNM stage, gross and histologic types, and location and size of the lesions were retrospectively analyzed for patients with primary lesions not visualized on preoperative MDCT.
  
  
  RESULTS
  In 44 patients with nonvisualized primary lesions, most (98%) of the lesions were stage pT1 confined to the mucosa (n = 27) or involving the submucosal layer (n = 16). Only one (2%) of the lesions had regional lymph node metastasis (pN1). Most (64%) of the lesions were located in the lower third of the stomach. Forty-one early gastric cancer lesions were flat, depressed, or excavated, and only two were elevated. Depending on the depth of invasion (mucosa or submucosa), there were no statistical differences (p > 0.05) in size, location, and gross or histologic type.
  
  
  CONCLUSIONS
  Almost all primary lesions of gastric cancer not visualized on preoperative MDCT with an optimized imaging protocol are early gastric cancer without regional lymph node metastasis. This negative finding may be helpful in planning minimally invasive management of gastric cancer.
authors.affiliation: Department of Radiology, Yonsei University College of Medicine, YongDong Severance Hospital, 146-92 Dogok-Dong, Gangnam-Gu, Seoul 135-720, Republic of Korea.
authors.forename: Jeong-Sik
authors.initials: JS
authors.lastname: Yu
authors.forename: Seung Ho
authors.initials: SH
authors.lastname: Choi
authors.forename: Won Hyuk
authors.initials: WH
authors.lastname: Choi
authors.forename: Jae-Joon
authors.initials: JJ
authors.lastname: Chung
authors.forename: Joo Hee
authors.initials: JH
authors.lastname: Kim
authors.forename: Ki Whang
authors.initials: KW
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005743:Gastrectomy; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011300:Preoperative Care / Q000379:methods; D011856:Radiographic Image Enhancement / Q000379:methods; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013274:Stomach Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery*; D014057:Tomography, X-Ray Computed / Q000379:methods*