ASSESSMENT OF EMBRYONIC ANATOMY AT 6-8 WEEKS OF GESTATION BY INTRAUTERINE AND TRANSVAGINAL SONOGRAPHY

Our purpose was to compare the ultrasound visualization of the early f irst-trimester embryo using transvaginal and intrauterine sonography, In all, 32 women about to undergo therapeutic abortion at 6-8.9 weeks gestation were studied using a specially developed catheter-based, hig h-resolution, real-time miniature (2.4 mm outer diameter) ultrasonogra phy transducer (20 MHz). Before the intrauterine sonographic procedure was performed, transvaginal sonographic assessment of the embryo was conducted, The parameters evaluated included the ability to visualize anatomical structures and a subjective assessment of the overall image clarity. The ability to view most organs was better with intrauterine sonography compared to transvaginal sonography, and this was especial ly true for the brain, spine, heart, liver, midgut herniation, extremi ties, and sacral tail, Moreover, it was possible to obtain finer image quality of very small embryonic structures,vith intrauterine sonograp hy than,vith transvaginal sonography, Stomach, spleen, kidney, and bla dder could not be depicted with both techniques, One cystic hygroma wa s diagnosed at 7 weeks 6 days using intrauterine sonography, but not w ith transvaginal sonography, Intrauterine sonography may provide addit ional information on the visualization of anatomical structures of the embryo in the early first trimester of pregnancy, In this limited ser ies, one case of cystic hygroma was demonstrated and, thus, there is a potential for its use in the early detection of embryonic malformatio n, These results suggest that intrauterine sonography may be a valuabl e tool in imaging the early first-trimester embryo, complementing and not replacing transvaginal sonography in high-risk pregnancies.