Three-dimensional ultrasound in fetal medicine after 25 years in clinical practice: many advances and some questions

Radiol Bras. 2016 Set/Out;49(5):V–VI The first three-dimensional ultrasound system (3D-US) in obstetrics was proposed by Baba et al. in 1986 and consisted of a mechanical arm attached to a two-dimensional convex probe that was able to capture two-dimensional images, which were sent to a computer and processed into three-dimensional volumes. However, the long time required for processing and the low quality of the images impeded their clinical application. In the early 1990s, the advent of automatic scanning volumetric probes opened new horizons in the three-dimensional evaluation of the fetus. In 1992, Kuo et al. demonstrated the first application of 3D-US fetal evaluation. Since then, various applications of 3D-US in fetal medicine have been described, such as the evaluation of fetal malformations, volumetric assessment of fetal organs, cardiac assessment, evaluation of the central nervous system, and the use of power Doppler. More recently, new software, such as HDlive, allow a realistic vision of the face and surfaces of the fetus. The main advantages of 3D-US would be the following: evaluation of a fetal structure simultaneously in the three orthogonal planes; fetal assessment in the absence of the mother; less reliance on operator skills; and the possibility of sending three-dimensional volumes for analysis at tertiary care centers. At 25 years after the introduction of 3D-US in the clinical practice of fetal medicine, despite the greater availability of devices that are faster and produce images with higher resolution, as well as the involvement of examiners who are more experienced in the technique, questions remain about the real advantage in relation to the two-dimensional ultrasound (2D-US) for the maternal-fetal dyad. In this issue of Radiologia Brasileira, Werner et al. present the experience of their group in the construction of virtual and physical 3D models of 26 singleton fetuses and 5 twin fetuses with various malformations, obtained through 3D-US, magnetic resonance imaging (MRI), and computed tomography (CT). The authors state that additive manufacturing technology allows the conversion of a virtual 3D model to a physical model, with precise dimensions, in a process that is fast and easy. They conclude that