1/6. Sirenomelia sequence: first-trimester diagnosis with both two- and three-dimensional sonography.OBJECTIVE: To describe the sonographic findings of sirenomelia during the first trimester on both two-dimensional sonography with color Doppler imaging and three-dimensional sonography. methods: Two cases of sirenomelia in primiparous patients with histories of infertility are described. The diagnosis was made on the basis of two-dimensional sonography, and three-dimensional sonography was used to further characterize the findings. RESULTS: Both fetuses had size-date discrepancies, increased nuchal translucency, large intra-abdominal vessels, and 2-vessel umbilical cords. Both pregnancies were terminated by dilation and curettage after the patients viewed the three-dimensional pictures of the fetuses. CONCLUSIONS: During the first trimester of pregnancy, rare and lethal anomalies can be diagnosed with a high degree of confidence if a thorough, age-dependent anatomic survey of the fetus is performed.- - - - - - - - - - ranking = 1keywords = vessel (Clic here for more details about this article) |
2/6. Recurrent tetraamelia and pulmonary hypoplasia with multiple malformations in sibs.A term amelic female infant was born to an apparently nonconsanguineous Arab Moslem couple. This was followed by the birth of 4 normal children. Afterwards, in 2 subsequent pregnancies, 2 amelic fetuses were diagnosed by transabdominal ultrasonography in the 18th and 12th week of gestation. Pregnancies were terminated and on autopsy both amelic fetuses had severe lung hypoplasia and aplasia of the peripheral pulmonary vessels. The first fetus also had apparently low-set ears and micrognathia, whereas the last had hydrocephaly and left cleft lip beside the lung hypoplasia and aberrant pulmonary artery. This appears to be a new autosomal recessive malformation syndrome.- - - - - - - - - - ranking = 0.5keywords = vessel (Clic here for more details about this article) |
3/6. Vascular steal: the pathogenetic mechanism producing sirenomelia and associated defects of the viscera and soft tissues.dissection of the abdominal vasculature in 11 cases of sirenomelia has demonstrated a pattern of vascular abnormalities that explains the defects usually found in this condition. The common feature is the presence of a single large artery, arising from high in the abdominal cavity, which assumes the function of the umbilical arteries and diverts nutrients from the caudal end of the embryo distal to the level of its origin. The steal vessel derives from the vitelline artery complex, an early embryonic vascular network that supplies the yolk sac. Arteries below the level of this steal vessel are underdeveloped and tissues dependent upon them for nutrient supply fail to develop, are malformed, or arrest in some incomplete stage. In contrast to the prevailing view that sirenomelia arises by posterior fusion of the two developing lower limbs, these studies suggest that the single lower extremity in sirenomelia arises from failure of the lower limb bud field to be cleaved into two lateral masses by an intervening allantois.- - - - - - - - - - ranking = 1keywords = vessel (Clic here for more details about this article) |
4/6. Aplasia of the radial artery.A 2-year-old girl with asymmetrical upper limbs and underdevelopment of the bones of the left forearm, wrist and hand with associated muscular and osteal hypoplasia is described. Doppler ultrasonography of the arterial trunks of the upper limb suggested a normal ulnar trunk in the left upper arm, an arterial vessel extending from the bend of the elbow to the distal third of the forearm, and the absence of any other arterial trunks in the radial region. angiography confirmed that vascularization of the forearm was sustained by the ulnar artery, which supported the dorsal arch of the carpus and digital arteries arising from it. The interosseal artery was morphologically normal but there was aplasia of the radial artery. It is suggested that this malformation is the result of suppressed development of the vascular system of the left radial segment as other pathologies normally associated with the condition were absent.- - - - - - - - - - ranking = 0.5keywords = vessel (Clic here for more details about this article) |
5/6. prenatal diagnosis of sirenomelus with color Doppler ultrasonography.Sirenomelus is an invariably lethal congenital anomaly characterized by complete or nearly complete fusion of the lower extremities that occurs in 1 of 60,000 births. In about 50% of cases this condition cannot be diagnosed prenatally because of the associated oligohydramnios that precludes a detailed examination of the fetus. We present a case of sirenomelus in which prenatal diagnosis was aided by color Doppler ultrasonography; visualization of the vitelline artery as a single, large intraabdominal vessel that did not branch in the fetal pelvis but rather coursed ventrally into the umbilical cord proved to be diagnostic of this rare condition. color Doppler flow ultrasonography is a valuable tool for the prenatal diagnosis of sirenomelus.- - - - - - - - - - ranking = 0.5keywords = vessel (Clic here for more details about this article) |
6/6. Sirenomelia sequence versus renal agenesis: prenatal differentiation with power Doppler ultrasound.In order to assess the role of power Doppler ultrasound in the prenatal diagnosis of sirenomelia, prenatal findings in two fetuses with the sirenomelia sequence and in seven with bilateral renal agenesis were reviewed and compared. Both conditions were characterized by absence of renal vessels. However, the two common iliac arteries were always visualized in fetuses with renal agenesis, whereas absence of distal branching of the main abdominal vessel was a characteristic feature of sirenomelia. Power Doppler ultrasound allows expeditious identification of absent or non-functional renal arteries in fetuses with severe oligohydramnios. In addition, incorporation of power Doppler imaging to identify the aortic bifurcation could provide a diagnostic feature that could assist in the prenatal diagnosis of sirenomelia and in the differential diagnosis with other causes of bilateral renal agenesis.- - - - - - - - - - ranking = 1keywords = vessel (Clic here for more details about this article) |