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Abstract
Duplex Doppler Ultrasound is a quick, easy and cheap imaging process for assessment of Gestational Trophoblastic Disease, it is however dependent on the skill and experience of the operator who needs to be suitably trained to perform it. (Jonathan S. Berek 2007)
Gestational trophoblastic disease consists of four different neoplastic diseases including ; complete and partial molar pregnancies, invasive hydatidform mole, choriocarcinoma as well as placental site trophoblastic tumor. These entities vary in their propensity for local invasion and metastasis. (David M. Lusely et al 2004)
Concerning complete moles , real time B mode scan might not be able to identify small molar changes in early trimesteric pregnancy, or to distinguish early mole from degenerating villi, or may give false impression of a blighted ovum. In such cases Transvaginal color coded flow and Duplex Doppler ultrasound reveals highly vascularized areas in close proximity to gestational sac with very low resistance values compared to normal pregnancy of the same gestational age. (Kurjak, et al, 2001)
Diastolic flow is larger and resistance (RI) is much lower in uterine, arcuate, radial and spiral arteries in the mole than in normal pregnancy. Also RI was low in the molar flow i.e; in the intervesicular spaces. (K. Maeda ,et al, 2006)
Real time B mode scan may not be able to identify partial molar changes. Using transvaginal color Doppler ultrasound, zones of vascularization are seen in molar vesicles beside the fetus. As in complete mole diastolic flow is larger and resistance (RI) is much lower in uterine, arcuate, radial and spiral arteries in the mole than in normal pregnancy. Also RI was low in the molar flow i.e; in the intervesicular spaces. (K. Maeda ,et al, 2006)
Using transvaginal color Doppler technique, trophoblastic invasion into myometrial tissue can be easily recognized as prominent color coded zones in myometrium and high velocity, low resistance pattern displayed by pulsed wave Doppler. These signals arise from preexisting uteroplacental blood vessels (spiral arteries as well as radial and arcuate arteries) and is characterized by low resistance blood flow pattern. Sometimes the anatomical identification of the normal spiral and radial vessels is not possible due to the presence of newly formed tumoral vessels yet all these vessels are characterized by low resistance high velocity patten. These vessels are located in myometrium , and because of that they are very conclusive in diagnosis of invasive mole. Shimamoto and coworkers reported that invasive mole is the best indication for color Doppler flow mapping because of the total absence of false negative results. (Shimamoto, K., et al, 2002)
Using transvaginal color Doppler technique, choriocarcinoma develops a typical hot area representing preexisting and newly formed blood vessels. All of these vessels show very high velocity, and low resistance pattern displayed by pulsed wave Doppler. Differential diagnosis of choriocarcinoma from an invasive mole is important because