BACKGROUND Right-sided ligamentum teres (RSLT) is a congenital anomaly that is sometimes encountered during hepatobiliary surgeries. However, a valid protocol for describing the segmental anatomy of livers with RSLT has not been established, and confusions or anatomic misunderstandings have been a major problem. METHODS The vascular architecture and morphological characteristics were investigated in 35 livers with RSLT using three-dimensional (3D) simulations. RESULTS Couinaud's four sectors and three hepatic veins were clearly distinguished in the liver with RSLT using 3D simulations. The ligamentum teres was connected with the right paramedian portal pedicle, and the long axis of the cystic fossa was always observed on the left of the ligamentum teres in all 35 livers. However, when the main portal scissura was visualized using 3D simulation, the gallbladder was always located on the border of either side of the hemilivers, and the malposition of the gallbladder was not confirmed. CONCLUSIONS Although the right-sided components of the livers are well developed as a result of the right-dominant distribution of the feeding vessels in livers with RSLT, the basic segmental structure defined by the four sectors and the three hepatic veins are as well preserved as those in the typical liver anatomy.

The transcriptional programs that regulate blood vessel formation are largely unknown. In this paper, we examine the role of the zinc finger transcription factor LKLF in murine blood vessel morphogenesis and homeostasis. By in situ hybridization and immunohistochemistry, we show that LKLF is expressed as early as embryonic day 9.5 (E9.5) in vascular endothelial cells throughout the developing mouse embryo. To better understand the function of LKLF, we used homologous recombination in embryonic stem (ES) cells to generate LKLF-deficient (LKLF-/-) mice. Both angiogenesis and vasculogenesis were normal in the LKLF-/- mice. However, LKLF-/- embryos died between E12.5 and E14.5 from severe intra-embryonic and intra-amniotic hemorrhaging. This bleeding disorder was associated with specific defects in blood vessel morphology. Umbilical veins and arteries in the LKLF-/- embryos displayed an abnormally thin tunica media and aneurysmal dilatation before rupturing into the amniotic cavity. Similarly, vascular smooth muscle cells in the aortae from the LKLF-/- animals displayed a cuboidal morphology and failed to organize into a compact tunica media. Consistent with these findings, electron microscopic analyses demonstrated endothelial cell necrosis, significant reductions in the number of vessel-wall pericytes and differentiating smooth muscle cells, and decreased deposition of extracellular matrix in the LKLF-/- vessels. Despite these defects, in situ hybridization demonstrated normal expression of platelet-derived growth factor B, Tie1, Tie2, transforming growth factor beta, and heparin-binding epidermal growth factor in the vasculature of the LKLF-/- embryos. Therefore, LKLF defines a novel transcriptional pathway in which endothelial cells regulate the assembly of the vascular tunica media and concomitant vessel wall stabilization during mammalian embryogenesis.

OBJECTIVE: To assess a possible relationship between ductus venosus blood flow abnormalities and cardiac defects in chromosomally normal fetuses with increased nuchal translucency thickness at 10-14 weeks of gestation. METHODS: Ductus venosus Doppler ultrasound blood flow velocity waveforms were obtained at 10-14 weeks' gestation immediately before fetal karyotyping in 200 consecutive singleton pregnancies with increased nuchal translucency. Fetal echocardiography was subsequently carried out in those with normal fetal karyotype. RESULTS: Reverse or absent flow during atrial contraction was observed in 11 of the 142 chromosomally normal fetuses with increased nuchal translucency. Major defects of the heart and/or great arteries were present in seven of the 11 with abnormal ductal flow and increased nuchal translucency, but in none of the 131 with normal flow. CONCLUSION: These preliminary results suggest that abnormal ductus venosus blood flow in chromosomally normal fetuses with increased nuchal translucency identifies those with an underlying major cardiac defect.

Hypergalactosaemia was discovered in a newborn girl during routine metabolic screening. Hereditary enzyme deficiency was ruled out. Because hypergalactosaemia persisted, an open ductus venosus Arantii was suspected but remained undetected by conventional two-dimensional ultrasonography. It was demonstrated by combined colour and pulsed wave Doppler sonography. At age 3 years 6 months, the girl developed initial symptoms of portosystemic encephalopathy which progressed and was treated by protein restriction, oral lactulose and flumazenil, with some success. In the absence of enzyme deficiency, hypergalactosaemia in the newborn is an early sign of duct persistence. For the unambiguous diagnosis of an open duct, colour Doppler sonography is the method of choice. Pulsed wave Doppler sonography is recommended for pathophysiological characterisation of the splanchnic venous return.

Vascular anomalies of the umbilical cord and fetus were evaluated with ultrasound in 11 fetuses. The anomalies included true knot of the cord (n = 1), umbilical vein varix (n = 1), persistent right umbilical vein (n = 1), and unilateral hypertrophy of the iliac artery in cases of a single umbilical artery (n = 8). One fetus with a single umbilical artery had a meningocele, hydrocephalus, and polyhydramnios; another had mitral atresia. The other fetuses were healthy except for the vascular abnormalities. A previously unreported finding in the identification of a single umbilical artery is described.

OBJECTIVE To assess the clinical significance of the absence of the ductus venosus. DESIGN A retrospective study with a review of the literature. METHODS The archives of our ultrasound laboratory and the English literature were searched for cases with a prenatal diagnosis of absence of the fetal ductus venosus. RESULTS Between 1985 and 2000, 10 fetuses were diagnosed in our center as having absence of the ductus venosus. The review of the literature revealed 23 cases. Three main patterns of abnormal venous circulation were documented:(1) umbilical vein bypassing the liver and connecting directly to the right atrium (46%);(2) umbilical vein bypassing the liver and connecting to the inferior vena cava mostly through one of the iliac veins (25%);(3) umbilical vein connecting to the portal circulation without giving rise to the ductus venosus (21%). Major anomalies, including chromosomal aberrations, were found in 8/33 (24%) cases. Hydrops developed in 11/33 (33%) cases. Twenty fetuses with isolated absence of the ductus venosus were delivered, and 5 (20%) died. The portal vein was found to be absent in half of the infants examined after birth. CONCLUSIONS Our results and the review of literature suggest that absence of the ductus venosus is associated with a high incidence of fetal anomalies and adverse outcomes, including associated malformations, chromosomal aberrations, in utero heart failure and absence of the portal vein. Heart failure and absence of the portal vein seem particularly frequent when absence of the ductus venosus is associated with a connection of the umbilical vein to either the inferior vena cava or the right atrium.

OBJECTIVE To present our experience in the prenatal diagnosis of anomalies of fetal veins using high-resolution color Doppler ultrasound. DESIGN An observational study of 16 fetuses with abnormalities of the umbilical, portal, hepatic and caval venous system being diagnosed at the Division of Prenatal Diagnosis and Therapy (Bonn, Germany) over the past 5 years. The abnormality of the venous system, the underlying embryologic disorder and the outcome of the pregnancy are presented and compared with the literature. RESULTS In group A, eight fetuses had an abnormal course of the umbilical vein with a patent (n = 3) or absent (n = 5) ductus venosus. No portal veins and absent or abnormal hepatic veins were visualized by color Doppler sonography. Six fetuses (75%) did not have an associated malformation and have survived. Two pregnancies with fetal hydrops due to a small heart and to Turner's syndrome were terminated or ended in fetal demise. In group B, seven of eight fetuses with an abnormal caval system had a situs ambiguus or an atrial isomerism. A cardiac defect was detected in six cases (86%). These six pregnancies ended in four terminations of pregnancy and two infant deaths due to the severity of the congenital cardiac defect. One child with a normal heart and a child with an isolated abnormal course of the lower inferior vena cava are developing well. CONCLUSIONS In a targeted fetal scan the course of the umbilical vein, ductus venosus, the portal and hepatic veins and inferior vena cava should be carefully examined using color Doppler. Any suspicious finding should be followed by a detailed assessment of the specificity of this abnormality taking into consideration the embryologic development of the fetal venous system together with the associated malformations.

Anomalies of the fetal umbilical vessels are rare, excepting single umbilical arteries which occur in 0.2-1.0% of pregnancies. Abnormalities of the intra-abdominal umbilical vein may be categorized into three main groups:(1) the ductus venosus is patient but the right umbilical vein persists;(2) the ductus venosus is not patent, and there is extrahepatic continuation of the umbilical vein; and (3) the umbilical vein takes a normal course but is abnormally dilated. We describe cases of each of these types of anomaly, including the first report of prenatal diagnosis of insertion of the umbilical vein into the iliac vein, and review the literature on this subject.

The persistence of a right umbilical vein is an uncommon finding, with only a dozen cases reported since 1826. The persistent right umbilical vein may replace the normal left umbilical vein or be supernumerary. The anomaly is associated with numerous and occasionally lethal malformations. In this series, only three of six fetuses (and another two in the literature) had no associated anomalies. All the others had a variety of associated lesions ranging from minor to lethal. The appearance at ultrasound is easy to recognize: The intrahepatic portion of the umbilical vein is lateral to the gallbladder, and the portal vein curves toward the stomach, instead of parallel to it. Since the recognition of the persistent right umbilical vein is simple and does not require additional scanning (it is visible in the section used to measure the abdominal perimeter), the author suggests using it as an indicator for more in-depth scanning.

OBJECTIVE The purpose of this study was to define the association between unequal placental sharing and birth weight discordance in monochorionic/diamniotic twin pregnancies. STUDY DESIGN The study comprised a prospective cohort of monochorionic/diamniotic twin pregnancies who were delivered in Kaiser Permanente-Northern California, 1997-2003. Dye injection studies of fresh postpartum placentas were performed. Placental sharing, cord insertion combinations, vascular anastomoses, gestational age, and birth weights were recorded. Statistical comparisons of birth weight and gestational age were made with the Student t test. Rates of birth weight discordance were compared with the chi-square test. Multivariate logistic regression models analyzed the relationship between variables of interest. RESULTS Mean birth weights for larger and smaller twins were 2400 g and 2109 g, respectively. Twenty-two percent of the monochorionic/diamniotic twin pairs had birth weight discordance > or = 20%, and 8% of these pairs had twin-twin transfusion syndrome. Monochorionic/diamniotic twin pairs with unequal placental sharing had a 9.8 times greater likelihood of birth weight discordance (95% CI, 5.4-17.9) as compared with those pairs with equal placental sharing. CONCLUSION Unequal placental sharing is a significant risk factor for birth weight discordance in monochorionic/diamniotic twins. Antenatal diagnosis of unequal placental sharing would enable improved counseling in the setting of monochorionic/diamniotic twins.

We report a functioning ductus venosus with hypoplasia of the right hepatoportal system in a 2-year-old child born with asymmetric intra-uterine growth retardation. Postprandial galactosaemia and hyperammonaemia were clues to diagnosis of portal-systemic shunt through the patent ductus venosus, which was confirmed by ultrasonography and angiography.