COLOR DOPPLER IMAGING IN THE EVALUATION OF NORMAL AND ABNORMAL EARLY UTEROPLACENTAL CIRCULATION AND GESTATIONAL OUTCOMES

The advent of color Doppler imaging in combination with high-resolutio n transvaginal ultrasonography has extended the use of this modality t o in-vivo functional assessment of early uteroplacental circulation. T he anatomy of the early circulation may be described which may then be studied in combination with the functional assessment to characterize the pathophysiology of normal and abnormal first trimester circulatio ns. During the first trimester of normal gestation color Doppler imagi ng shows low resistance to flow in the spiral arteries and absence of arterial blood flow within the intervillous space. In abnormal first t rimester gestations important changes occur in the uteroplacental circ ulation which may be detected by color Doppler imaging. Color Doppler data of normal first trimester pregnancies characteristically demonstr ate low resistance to flow in the decidual arteries and absence of art erial flow within the intervillious spaces. In abnormal pregnancies hi gh resistance to flow is demonstrated in the same decidual vessels and diffuse pulsitile flow is detected within the intervillious space. Co lor flow Doppler ultrasonography is an extremely important imaging mod ality in the prediction of gestational outcome. This type of imaging m ay be employed in the assessment of pregnancies demonstrating clinical signs of early embryonic failure and may be used to evaluate the effi cacy of therapies initiated for the prevention of miscarriage.