hree-dimensional (3D) and 4-dimensional (4D) volume sonography of the female pelvis is one of the most important advances in women's imaging in recent years-in most centers and practices, it has already replaced magnetic resonance imaging (MRI) and computed tomography (CT) for many pelvic imaging indications. Three-dimensional sonography has enabled the user to move sonography into the new era of rapid, automated, and comprehensive imaging, with displays similar to volume imaging that has been an integral part of CT and MRI for several decades. Currently available 3D/4D volume sonography can generate images of the female pelvis that are very similar in orientation and quality to those of MRI and CT. Patients now referred specifically for 3D sonography would previously have required MRI, a far more costly and time-consuming procedure.This article will demonstrate the necessity of 3D sonography as a diagnostic procedure for many pelvic conditions previously requiring MRI or CT. At the same time, it will call on the insurance industry in the United States to reevaluate the current reimbursement policies for 3D sonography, as they currently remain spotty at best, preventing many practitioners from ordering these studies. Since CT and MRI can also provide a diagnosis of many pelvic conditions, referring physicians are often forced to order these costly imaging studies rather than the more patient-friendly imaging now possible with 3D sonography often because of reimbursement.
What Is 3D Sonography?Three-dimensional sonography has the important ability to acquire volume data of the female pelvis that can be processed for display of reconstructed views that are not accessible with traditional 2-dimensional (2D) sonography. Initially, the examiner identifies and sets the region of interest, incorporating all structures of interest at the narrowest angle possible and at a speed to achieve the highest resolution. The examiner then activates the transducer (either mechanical or electronic matrix) to acquire the volume automatically. Any view within the volume can then be reconstructed and dis-