study in which they compared the effect of different depth cues on vessel visualizations. Based on the results of their study, they conclude that pseudo-chromadepth and the use of fog achieve the best improvement in depth perception.

Encoding depth information as colors on the vessel surfaces has been proven to be effective in communicating depth. However, these techniques limit the information presented on the vessels to depth information. Domain experts are often interested in visualizing also other properties on top of the vessels. This problem was addressed by Behrendt et al. [@Behrendt2017] who combined pseudo-chromadepth with additional information on top of the vessels. They used the pseudo-chromadepth color scheme to shade the areas close to the contour by applying a blending mask inspired by Fresnel equations. To represent the additional information they used a discretized color scale which reduced ambiguity between the surface color and the pseudo-chromadepth scale. Lawonn et al. [@Lawonn2014] combined different techniques to convey depth together with vessel flow visualization, accurately resolving at the same time occlusions between different vessels. Borkin et al. [@Borkin2011] used the surface of the vessel together with a 2D representation of them to communicate endothelial shear stress.

Design Goals for Vessel Visualization 