Material and Method: A retrospective study was performed in 50 patients with gastric cancer who underwent 64-slice MDCT. The patients were enrolled between January 2006 and March 2011. The MDCT scan of abdomen from patients with gastric cancer was retrospectively evaluated by two gastrointestinal radiologists without knowledge of each patient’s history, clinical data, and final diagnosis. Readers recorded the presence or absence of ascites, increased peritoneal fat density, peritoneal thickening or enhancement, and peritoneal nodule or mass. Sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of CT scan were calculated.

Results: Twenty-five patients from 50 patients indicated presence of peritoneal metastasis. The accuracies of 64-sliced MDCT of ascites, increased peritoneal fat density, peritoneal thickening/enhancement, and peritoneal nodule are 80.00, 80.00, 68.00, and 84.00%, respectively.

Conclusion: The 64-slice MDCT is a non-invasive imaging method that can be used for diagnosing staging gastric cancer with carcinomatosis peritoneii. It is an important tool for further investigation and proper treatment. Peritoneal nodules, increased peritoneal fat density, ascites, and peritoneal thickening/enhancement are ancillary signs suggestive of peritoneal carcinomatosis. However, in equivocal cases of imaging study, further investigation with laparoscopy is suggested to rule out small or miliary peritoneal metastasis.

Keyword: Gastric cancer, Stomach neoplasm, Peritoneal metastasis, Peritoneal carcinomatosis, Peritoneal spreading