Surface-rendering imaging of gastrointestinal lesions by three-dimensional endoscopic ultrasonography

In three-dimensional endoscopic ultrasonography (3D-EUS), a surface-rendering method can provide both a surface image and a cross-sectional ultrasonographic image. We evaluated the usefulness of this imaging method for digestive tract lesions.

A total of 30 patients underwent 3D-EUS with surface-rendering using a 3D probe system which arranged individual radial scanning images into 128 points on a computer monitor to outline the surface of a lesion. A complete surface image of the lesion was displayed on the computer monitor using lines obtained from 40 radial scanning images.

Surface-rendering images of lesions were similar to endoscopic images. The surface-rendering method permitted precise correlation of two-dimensional images depicting a slice of a lesion with the corresponding surface of the lesion. Unlike conventional endoscopy, this approach permitted observations of lesions at any desired angle. Complete images of lesions were achieved in 14 patients and were half-completed in another five, but could not be obtained in 11 patients: in six the distance between the lesion and the 3D probe was too short to avoid artifacts, while in five the lesion was larger than the longitudinal scanning length of 4 cm or greater than 90 in extent in radial scanning images. Artifacts caused by heartbeat led to irregular images in four patients, including three with esophageal cancer and one with gastric cancer.

Despite some problems, surface-rendering imaging should prove useful for diagnosis, and the method will improve as software is perfected.