Helical CT of the stomach: differentiation between benign and malignant pathologies, together with the staging of gastric carcinoma.

OBJECTIVES

To evaluate the capacity of Helical Hydro-CT to differentiate between benign and malignant gastric pathologies, and also to measure its usefulness in the staging of gastric carcinoma.

PATIENTS AND DESIGN

We perform a cross-sectional study to evaluate the diagnostic efficacy of CT, including patients prospectively. We study 92 patients with a clinical suspicion of gastric pathology using helical CT with a contrast agent (HCTC), water being the oral contrast agent, and i.v. iodine contrast. According to the findings of previous works, we considered stomachs to be normal when the thickness of their wall was less than or equal to 6 mm, with a multilayered appearance that stands out homogeneously with the i.v. contrast. A malignant tumour was diagnosed if the thickness of the wall was greater, together with strong marking by the contrast agent and loss of the normal multilayered pattern. Parietal thickening was classified as gastritis if there was no excessive marking and no loss of the layered pattern. Masses with smooth borders, intraluminal growth and a rounded morphology were diagnosed as sub-mucosal tumours. The results of our 92 studies were compared in all cases with the findings of endoscopic studies, while in the 52 patients treated with surgery they were compared against surgical findings.

RESULTS

In 12 of the 92 patients studied using HCTC no gastric pathology was observed by CT or endoscopy. Of the 80 pathological cases CT was used to diagnose 29 as benign pathology, 19 of which were confirmed as such by histology, and 51 cases as malignant pathology, of which 49 were confirmed by histology. We obtained a sensitivity of 81.7% in the diagnosis of malignant pathology and a specificity of 90%, with a PPV of 96% and a NPV of 62%. Regarding TNM staging (in comparison with the 1997 TNM classification), the diagnostic reliability obtained amounted to 56% for T and N, and 87% for M.

CONCLUSIONS

Helical hydro CT makes it possible to diagnose advanced gastric carcinoma. Its usefulness basically lies in the evaluation of metastatic neoplastic disease. It has also been shown to be useful in the diagnosis of benign pathologies. It is not a good screening method for the diagnosis of gastric carcinoma.