Although any available 2–8 MHz abdominal probe can be used for scanning of the pelvic floor, the images in this book are from a BK abdominal probe used for transperineal imaging unless specified otherwise (Fig. 2.2, Table 2.2).

High-resolution 3D allows the automatic acquisition and construction of high-resolution data volumes by synthesis of a high number of parallel transaxial or radial 2D images, ensuring that true dimensions in all three x, y, and z planes are equivalent. The constructed data cube technique provides accurate distance, area, angle, and volume measurements. The volume rendering technique resulting from high-resolution 3D provides accurate visualization of the deeper structures. High-resolution endovaginal or endoanal anatomy can be obtained in 30–60 s. The scanned data set is also highly reproducible, with limited operator dependency. The probe can visualize all rectal wall layers; evaluate the radial, longitudinal extension of sphincter tears ; and measure detailed pelvic floor architecture in all x, y, and z planes accurately (Fig. 2.3).

The 3D volume can be used on the scanner, but the ease of use and functionality are better when the free software is installed on any PC (Fig. 2.12). The available functions are lined to the right, bottom, and the left side of the screen. One can scan any patient and export their data files to a CD, DVD, USB, external hard drive, or a server, and then view them at any time on any PC. This is akin to the virtual examination of the patient. The work can be saved and reproduced with ease. On the left side there is an “eye” icon where you can create “memory points.” By clicking on the eye icon, you save the 3D view and find it easily for documentation or research purposes at a later time (Fig. 2.13). Below the eye icon is the annotation and arrow icon for writing and marking structures on the 3D volumes (Fig. 2.14). The third icon on the left is the measurement icon. You can obtain linear measurement, angle, area, and volume measurements. When in the measurement mode, additional icons appear on the upper right side that allow you to undo or delete all your measurements (Fig. 2.15). The fourth icon on the upper left of the screen is the sculpting icon. One can cut the structures out (Fig. 2.16) or cut the inner structures (Fig. 2.17). Alternately, a structure can be isolated altogether (Fig. 2.18). The next four icons on the middle left of the screen are for taking snapshots, including the wire frame, removing the personal data, and saving the volumes (see Fig. 2.12). On the right side of the screen, there are two icons for adjusting the brightness and the hue. There is also an icon for changing the volume color to soft yellow, blue, or green (Fig. 2.19). On the bottom of the screen, there are icons for opening files, obtaining rendered views (Fig. 2.20). Volume render mode is a technique for the analysis of the information inside 3D volume by digital enhancing individual voxels. It is currently one of the most advanced and computer-intensive rendering algorithms available for computed tomography and can also be applied to high-resolution 3D ultrasound data volume. The typical ray/beam-tracing algorithm sends a ray/beam from each point (pixel) of the viewing screen through the 3D space rendered. The beam passing through the volume data reaches the different elements (voxels) in the data set. Depending on the various render mode settings, the data from each voxel may be stored as a referral for the next voxel and further used in a filtering calculation, may be discarded, or may modify the existing value of the beam. The final displayed pixel color is computed from the color, transparency, and reflectivity of all the volumes and surfaces encountered by the beam. The weighted summation of these images produces the volume-rendered view. The render mode is useful for visualization of tapes and meshes that may seem isoechoic due to dense tissue ingrowth. The dark colors appear darker and the light colors appear lighter in rendered mode and anything in between has lesser intensity.