Three-dimensional ultrasound study of fetal craniofacial anatomy

Ultrasound has placed itself in a strong position as an imaging technique in day to day obstetric care. This is the result of many advantages over techniques such as MRI (magnetic resonance imaging) and CT (computer tomography), in particular the flexibility of the technique, the moderate costs, the possibility of real-time imaging and the use of non-ionizing radiation.1 In the Netherlands, ultrasound is used on a regular basis in all obstetric units and by most regional midwifery services. During the last decades the image quality has strongly improved, partially due to the development of new ultrasound techniques. When using the technique of conventional two-dimensional ultrasound (2DUS) the ultrasonographer tries to form a mental three-dimensional (3D) picture of the fetal anatomy from two-dimensional (2D) planes. This process tends to become more difficult and time-consuming when the structure itself and the circumstances are more complicated, thus enhancing the risk of misinterpretation.2 This shortcoming of conventional ultrasound techniques opened up the way for three-dimensional ultrasound (3DUS) in fetal imaging at the beginning of the 90s.