WS16‐02Sonoembryology using intrauterine sonography

Our first purpose was to describe embryonic anatomic structures by use of IUS with a 20‐MHz flexible catheter‐based, high resolutions, real‐time miniature transducer. The number and the clarity of structures increased from 7 to 8 weeks of gestation; however, the image quality was degenerated because of the increasing fetal size at 9 weeks. At 8 weeks secondary brain vesicles, spine, midgut herniation, liver, upper and lower limb buds, and sacral tail were visualized in all fetuses. The four‐chamber view was first identified at 8 weeks, as were fingers or toes. The stomach was first noted at 9 weeks. Second purpose was to compare the ultrasound visualization of the early first‐trimester embryo using TVS and IUS as 6–8 weeks of gestation. The ability to view most organs was better with IUS compared to TVS, and this was especially true for the brain, spine, heart, liver, midgut herniation, extremities, and sacral tail. Moreover, it was possible to obtain finer image quality of very small embryonic structures with IUS than with TVS. Third purpose was to evaluate embryonic organ growth (liver, heart, and brain vesicles) using IUS in the early first trimester of pregnancy. The significant good correlation between each parameter and gestational age was obtained. Fourth purpose was to visualize normal embryonal surface anatomic structures using 3D‐IUS at 7–9.9 weeks gestational age. At week 8, prominent forehead was evident, and upper and lower limbs and midgut herniation were clearly depicted. At week 9, fingers and toes were depicted as small digital rays, and the sacral tail protruded caudally. At week 10, embryonic face and fingers were clearly shown.