Figure 16b. SSD and volume-rendered images of an inferior vena cava filter overlying the spine. (a) SSD creates an effective 3D model for looking at osseous structures in a more anatomic perspective than is achieved with axial images alone. It was used in this case to evaluate pelvic fractures not included on this image. (b) Volume rendering achieves a similar 3D appearance to allow inspection of the bone surfaces in a relatively natural anatomic perspective. In addition, the color assignment tissue classification possible with volume rendering allows improved differentiation of the inferior vena cava filter from the adjacent spine.