Two types of artifacts may appear in virtual computed tomographic endoscopic views of the aorta rendered at different threshold levels: pierced surface and floating shape artifacts. A positive correlation was found between mean attenuation of the aorta and the threshold levels at which these artifacts appeared. The correlation was statistically significant (0.71 < or = r < or = 0.86) for floating shape. An artifact-free threshold range can be predicted on the basis of aortic enhancement.