The volume-rendering technique uses computed tomography data to produce simulated images of conventional barium and endoscopic studies of the stomach. Various gastric lesions are detected on volume-rendered images, and submucosal tumors are easily differentiated from mucosal lesions by means of the overlying bridging fold. Lesions that are only manifested by a change of mucosal color (early gastric cancer type 2b) or a loss of mucosal detail (gastritis) are difficult to detect from volume-rendered images, however. In cases of gastric neoplasm and varix, both the extraluminal pathologies of the lesion and the relation between the intraluminal and extraluminal components can be evaluated simultaneously.
The increasing capability of computed tomography (CT) imaging to acquire volumetric data sets with near-isotropic voxels has resulted in the increased use of three-dimensional (3D) rendering techniques for clinical applications (1-3). Notably, volume rendering has inherent advantages over the more commonly used surface display and projection techniques (4-6). Volume rendering has no associated information loss, and perspective rendering is possible. Perspective rendering is an indispensable technique for virtual endoscopy and is a definitive tool for 3D image displays. Using this technique, body cavities or hollow viscera can be viewed from unique internal perspectives that simulate endoscopy. Virtual endoscopy has been mainly investigated in the tracheobronchial tree and colon and is a promising method for detecting and differentiating colorectal lesions (7,8).
Virtual endoscopy that combines the features of endoscopic viewing and cross-sectional volumetric imaging may provide enhanced diagnostic capability (7-10). In addition, interactive displays of correlated two-dimensional (2D) and various 3D displays using volume rendering in a multiwindow format may help the endoscopist or surgeon during preprocedural or preoperative planning. In this article, we present 3D volume-rendering images of various gastric lesions together with their conventional imaging and pathologic findings.