Narrow-band volume rendering for freehand 3D ultrasound

Volume rendering, the projection of volumetric intensity data into a 2D image, is finding an increasing number of applications across a diverse range of scientific disciplines. A key ingredient in the volume rendering recipe is a procedure to allow the user to specify a limited volume of interest, since rendering the entire volume is often too slow and also leaves the image full of clutter that obscures genuine structures of interest: this is particularly important for 3D ultrasound, where speckle noise has traditionally frustrated the successful application of volume rendering. This paper describes novel techniques, tuned to the specific needs of 3D ultrasound, for specifying these target volumes. The basic idea is to extend the familiar planar and non-planar reslicing tools, such that the reslice plane or surface is endowed with a certain thickness, producing a narrow-band volume. The attraction of such volumes is that they are simple to set up, limit the amount of clutter in the final renderings and, when thin, produce reslice-like images that are far less sensitive to the precise position of the reslice plane (or surface) than those generated by standard reslice algorithms. The paper includes full implementation details of both planar and non-planar narrow-band volume rendering, and describes several practical applications of the resulting tools.