HYBRID RENDERING OF MULTIDIMENSIONAL IMAGE DATA

The most important rendering methods applied in medical imaging are su rface and volume rendering techniques. Each approach has its own advan tages and limitations: Fast surface-oriented methods are able to suppo rt real-time interaction and manipulation. The underlying representati on, however, is dependent on intensive image processing to extract the object surfaces. In contrast, volume visualization is not necessarily based on extensive image processing and interpretation. No data reduc tion to geometric primitives, such as polygons, is required. Therefore , the process of volume rendering is currently not operating in real t ime. In order to provide the radiological diagnosis with additional in formation as well as to enable simulation and preoperative treatment p lanning we developed a new hybrid rendering method which combines the advantages of surface and volume presentation, and minimizes the limit ations of these approaches. We developed a common data representation method for both techniques. A preprocessing module enables the constru ction of a data volume by interpolation as well as the calculation of object surfaces by semiautomatic image interpretation and surface cons truction. The hybrid rendering system is based on transparency and tex ture mapping features. It is embedded in a user-friendly open system w hich enables the support of new application fields such as virtual rea lity and stereolithography. The efficiency of our new method is descri bed for 3-D subtraction angiography and the visualization of morpho-fu nctional relationships.