Value of nonvisualized primary lesions of gastric cancer on preoperative MDCT.

Objective: The purpose of this study was to retrospectively determine the value of nonvisualized primary lesions on preoperative MDCT of patients with gastric cancer.
Materials and 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.
Conclusion: 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.