Three-dimensional volume rendering of the tendons of the ankle and foot

Three-dimensional (3D) rendering is the process of creating two-dimensional (2D) images that convey the 3D relationships of an object or objects. In the past 10 years, the use of volume-rendering (VR) images has become a commonly used method of 3D display. The improved data sets that result from spiral and multidetector computed tomography, improved software, and more powerful workstations significantly improve radiologists' ability to create these images. The process by which these images are obtained is described. It is possible to simultaneously demonstrate the tendons and bones of the ankle and hindfoot using VR because of significant attenuation differences among the soft tissue, tendons, and bone: fat approximately -100, muscle approximately 30, tendon approximately 90, and bone approximately 250 to 500 Hounsfield units. These 3D images can be helpful in the care of patients with ankle/foot deformities resulting from trauma, idiopathic disorders, and arthritis. These images present a global image that provides improved understanding of the relationships of the bones and adjacent tendons.