Figure 10b. Limitations of 3D rendering technique. (a) Sagittal MPR image obtained in a 23-year-old man who sustained an acute twisting injury and presented with pain and swelling of the left ankle shows a small fracture of the anterior process of the calcaneus (arrow). (b, c) Neither a VR image of the bones (b) nor an SSD image (c) demonstrates the anterior process fracture.