Quantitative and qualitative comparison of volumetric and surface rendering techniques

The fidelity of visualizing craniofacial features using two modern three-dimensional (3-D) imaging algorithms-one employing surface and the other volume rendering-is examined. Each rendering technique is evaluated for its ability to display closed cranial sutures, loss of thin bone through partial volume averaging, and the presence of artifacts. Linear measurements of the orbits, foramina, and mounting holes were taken on the 3-D renderings and compared with direct measurements. Both techniques visualized the closed cranial sutures, orbits, mandibles, and teeth. The errors in linear measurement averaged less than 1.5 mm (root mean square) and were not statistically different between the two techniques. Errors are attributable to uncertainty in locating edges due to partial transparency (volume rendering) and suboptimal lighting. Both rendering techniques stiffer from step pattern and thin-bone artifacts. It is concluded that an algorithm for surface construction can provide detailed and accurate representation of the craniofacial anatomy