ULTRASONOGRAPHIC AND RADIOLOGIC VISUALIZATION OF THE DEVELOPING EMBRYONIC SKELETON

We investigated the development of the skeleton in the embryonic and e arly fetal period both with ultrasonography and radiology. Eight norma l embryos/fetuses were studied weekly with real-time transvaginal sono graphy between 8 and 16 weeks of gestation to establish the ultrasonog raphic characteristics of normal ossification. Additionally, ossificat ion was studied in radiographs obtained from five embryos/fetuses betw een 9 and 14 weeks of gestation. Ossification centers, visualized as i ncreased echogenicity of the bones, were recognized with ultrasonograp hy from 9 weeks onwards. The appearance of primary ossification center s as observed by transvaginal ultrasonography was at the same gestatio nal age or at most 1 week later than when obtained with radiography or whole-specimen staining techniques. Transvaginal ultrasonography enab les early visualization of ossification centers in the embryo and fetu s. Detailed knowledge of the development of ossification of the skelet on may contribute to early prenatal diagnosis of skeletal dysplasias.