PURPOSE: The purpose of this study is to assess the efficacy of axial CT imaging and 3D imaging by spiral CTin the detection and evaluation of gastric lesion. MATERIALS AND METHODS: Seventy-seven patients with pathologically-proven gastric lesions underwent axial CT and 3D imaging by spiral CT. There were 49 cases of advanced gastric carcinoma(AGC), 21 of early gastric carcinoma (EGC), three of benign ulcers, three of leiomyomas, and one case of lymphoma. Spiral CT was performed with 3-mm collimation, 4.5 mm/sec table feed, and 1-1.5-mmreconstruction interval after the ingestion of gas. 3D imaging was obtained using the SSD technique, and on analysis a grade was given(excellent, good, poor). Axial CT scan was performed with 5-mm collimation, 7mm/sectable feed, and 5-mm reconstruction interval after the ingestion of water. RESULTS: Among 49 cases of AGC, excellent 3D images were obtained in seven patients (14.3%), good 3D images in 30(61.2%), and poor 3D images in12(24.5%). Among the 12 patients with poor images, the cancers were located at the pyloric antrum in eight cases, were AGC Borrmann type 4 in three cases, and EGC-mimicking lesion in one case. Using axial CT scan alone, Borrmann's classification based tumor morphology were accurately identified in 67.3% of cases, but using 3D imaging, the corresponding figure was 85.7%. In 33 cases receiving surgery, good correlation between axial CT scanand pathology occurred in 72.7% of T class, and 69.7% of N class. Among 21 cases of EGC, excellent 3D images were obtained in three patients (14.3%), good 3D images in 14 (66.7%), and poor 3D images in two (9.5%). The other twocases of EGC were not detected. By axial CT scan, no tumor was detected in four cases, and there were two doubtful cases. 3D images of three benign ulcers were excellent in one case and good in two. 3D images of three leiomyomas and one lymphoma were excellent. CONCLUSION: Combined axial CT imaging and 3D imaging by spiral CT has the potential to accurately diagnose gastric lesions other than AGC Borrmann type 4 or tumors located at the pyloricantrum.