Three-dimensional sonography in prenatal diagnosis: a luxury or a necessity?

Three-dimensional sonography revolutionized ultrasound imaging with its cap acity to depict an unlimited number of planes in which the object of intere st can be displayed. The addition of numerous modalities of image rendering promotes three-dimensional sonography to the top of the spectrum of diagno stic imaging in obstetrics and gynecology. The aim of this article is to pr esent our experience in 3-D sonography during the second and third trimeste r of pregnancy and to give a comparative review of literature. 247 patients in gestational age ranging from 12 to 40 weeks of gestation were examined over a three year period. The majority of patients entered the study becaus e fetal anomaly was suspected at two-dimensional sonography. Some patients were sent on to three-dimensional sonography because it was not possible to depict clearly normal fetal anatomy by two dimensional sonography. Out of 170 fetal anomalies three-dimensional sonographic analysis failed in only t hree cases. In all three anomaly was accompanied with severe oligohydramnio s. Main advantages of three-dimensional ultrasound in perinatal medicine an d antenatal diagnosis include scanning in the coronal plane, improved asses sment of complex anatomic structures, surface analysis of minor defects, vo lumetric measuring of organs, "plastic" transparent imaging of fetal skelet on, spatial presentation of blood flow arborization and, finally, storage o f scanned volumes and images. It is our decided opinion that three-dimensio nal sonography has gained a valuable place in prenatal diagnosis, becoming a necessity for every modern perinatal unit.