Advanced Techniques for Editing and Visualizing CTA Data

Spiral computed tomography (CT) allows for fast acquisition of a truly volumetric data set (Kalender et al. 1990). If contrast material is injected during scanning, the vasculature can be assessed in three dimensions. This procedure is named CT Angiography (CTA) and provides an excellent visualization of vessel lumina, stenoses and lesions (Napel et al. 1992). Contrast filled vessels share a common range of Hounsfield units with bone. Therefore, it is necessary to eliminate bone structures prior to 3D visualization. As interactive editing of bones, especially on a slice by slice basis, can be very time-consuming, we have developed a semi-automated technique (Slab-Editor) and various automatic methods for specific parts of the body, which minimize user interaction or even make it obsolete.