Volume imaging (3-D ultrasound) is particularly important in the diagnosis of the non-pregnant pelvis. Volume imaging is not new, as it has been used for decades in other forms of cross-sectional imaging such as CT and MR. Ultrasound, however, had been able to generate only thin, 2-D image slices that were taken solely in the acquisition plane and that were very operator-dependant and time-consuming. With 3-D ultrasound, any plane within the uterus and ovaries now can be demonstrated and, more importantly, can generate images of the pelvis that cannot be obtained with direct 2-D imaging. The coronal view of the uterus, therefore, can be demonstrated, showing the shape of the uterine cavity, the shape of the outside of the uterus, the location of any IUD, as well as the tubes and ovaries in orientations different from that usually demonstrated sonographically.

Images of the entire pelvis can be saved within the volume and rescanned by operators different - and perhaps with different expertise - from those who acquired the volume. This makes pelvic ultrasound far less operator-dependant and far more powerful in demonstrating pathologies not previously detectable sonographically.