Hydro-CT in patients with gastric cancer: preoperative radiologic staging

A total of 35 patients (age range 35-78 years) with gastric tumors on the lesser curve, or in the antro-pyloric region, underwent angio-CT in the prone position after filling the stomach with 500 ml of water and intravenous administration of glucagon. The films were reviewed by three radiologists independently, staging each tumor according to the TNM classification preoperatively. The overall accuracy of tumor staging ranged between 66-77 %, overstaging between 17-25 %, and understaging between 3-8.5 %. The diagnostic sensitivity, specificity, and accuracy for serosal invasion ranged between 90 and 100, 76 and 84, and 80-88 %, respectively, and the overall accuracy for N staging was 46, 48, and 51 % for the three observers. If, however, N1 and N2 tumors were considered as a single group, N-stage accuracy increased, ranging between 63 and 77 %. The "K test" for analyzing the interobserver agreement was 60 %, i. e., the diagnostic results are reproducible. Water filling of the stomach optimizes visualization of the gastric wall on contrast-enhanced CT. The prone position and drug-induced hypotony allows for good distension without any disturbing artifact reduction obscuring the lower gastric body.