3-D imaging of residual limbs using ultrasound

In this article, a method of using ultrasound to image a residual limb is presented. The method employs a compound scanning technique to reconstruct a cross-sectional image (a slice) of the limb in a transverse plane. By scanning the limb in many transverse planes, a three-dimensional (3-D) volumetric image can be obtained from which either a transverse slice, a longitudinal cross section, or a 3-D surface of the limb can be displayed. The compound process circumvents the problems associated with the large attenuation of bones and enables reconstruction of a complete image of bones and adjoining tissues. In addition, the compound process improves the lateral resolution and reduces the speckle noise. Results obtained from a pair of thin wires, a contrast-resolution phantom, and a human limb demonstrate the beneficial effects of the compound process. To maximize the benefits, however, an accurate pixel registration in image reconstruction is essential. Sources of pixel misregistration and the potential means of minimizing misregistration are discussed.