3-DIMENSIONAL ULTRASONOGRAPHY IN THE FIRST-TRIMESTER OF HUMAN-PREGNANCY

Our purpose was to visualize normal embryonal and fetal surface anatom ical structures in the first trimester of human pregnancy by use of th ree-dimensional ultrasonography with a specially developed abdominal t hree-dimensional transducer, Four embryos and 31 fetuses of 8-13 weeks gestation were studied with a specially-developed abdominal three-dim ensional transducer (3.5 MHz). This imaging system can provide convent ional two-dimensional ultrasonography images and can also generate, wi thin seconds, high-quality three-dimensional images in the surface and transparent mode with no need for an external workstation, The percen tage of surface anatomical structures visualized at each gestational a ge interval using two-dimensional and three-dimensional ultrasonograph y is presented, Head and trunk were depicted in all cases, The number and the clarity of visualization of face, upper and lower extremities, hand, and foot increased with advancing gestation, The free loop of t he umbilical cord was depicted in most cases, The number of depictions of abdominal cord insertion, midgut herniation, and yolk sac decrease d with the increase of gestation, Genitals could not be identified in the first trimester, The ability to view some surface anatomical struc tures (face, hand, and foot) was better with three-dimensional ultraso nography than with two-dimensional ultrasonography, Three-dimensional ultrasonography provides a novel means for visualization of surface an atomical structures of the embryo and early fetus, These results sugge st that three-dimensional ultrasonography can become an important moda lity in future embryological and early fetal research and in detection of embryonic and fetal developmental disorders in the first trimester of pregnancy.