Speaker: David Williams (City University London)
Curved Planar Reformation (CPR) has proved to be a practical and widely used tool for the visualization of curved tubular structures within the human body. It has been useful in medical procedures involving the examination of blood vessels and the spine. However, it is more difficult to use it for large, tubular, structures such as the trachea and the colon because abnormalities may be smaller relative to the size of the structure and may not have such distinct density and shape characteristics.
Our new approach (which we call 'Volumetric CPR') improves on this situation by using volume rendering for hollow regions and standard CPR for the surrounding tissue. This effectively combines gray scale contextual information with detailed color information from the area of interest. The approach is successfully used with each of the standard CPR types and the resulting images are promising as an alternative to virtual flythroughs.
We show that lighting is non-trivial because of the deformation which occurs when the three dimensional curved tubular structure is mapped to a two dimensional image plane. We show how lighting and shading is computed in this scenario and how it can be used to maximize the users understanding of the surface.
Lastly, we demonstrate that our new approach is a useful tool for displaying additional information not typically available during a flythrough, such as real-time surface coverage data or translucency rendering. We also show that, because the Volumetric CPR provides and alternative view on the colon, it increases surface coverage from 86.8% (for a flythrough in each direction) to 99.2%; significantly improving the chances of detecting abnormalities.