Flap valve of the heart foramen ovale revisited: macroscopic and histologic observations of human near-term fetuses.

We assessed the flap valve of the foramen ovale (FO valve) by examining 30 hearts from human fetuses of gestational age 30-40 weeks. We dissected the hearts, examined their macroscopic morphology, and then prepared semiserial sagittal sections across the valve. Although the primary septum is expected to extend along the left atrial face, eight hearts had a superior rim of the fossa ovalis on the left atrial face that was too thick and high, so there was no smooth continuation with the valve. Moreover, three of these eight hearts each had a flap valve that was fused with a long and narrow plate arising from the caval orifice. Histological analysis indicated that 21 specimens each had a candidate primary septum that contained myocardium, although the left sinuatrial valve (LSAV) contained fibrous tissue, but little or no myocardium. In each of 17 hearts, a candidate primary septum was attached to the left atrial face of the fossa, and parts of the LSAV extended to and approached the right atrial face. However, seven of these 17 hearts each had a folded small primary septum. Another four of these 17 hearts each had an LSAV that extended widely to the fossa, and a candidate primary septum (which might be a remnant) attached to the left atrial side of the LSAV. These variations suggest that the LSAV makes a major contribution to the FO valve in some fetal hearts. Consequently, the fetal FO valve appears to have heterogeneous morphology and origin.

Multidetector-row CT imaging evaluation of superior and inferior vena cava normal anatomy and caval variants: Report of our cases and literature review with embryologic correlation.

OBJECTIVE: To assess the potential of multidetector-row computed tomography imaging and its reformations in the evaluation of the superior and inferior vena cava normal anatomy and their anatomical variants, and to make a brief review of caval embryogenesis and developmental errors. METHODS: We retrospectively reviewed a total of 1000 whole-body computed tomography scans performed between January 2010 and December 2016 to assess the normal superior and inferior vena cava anatomy and their variants. RESULTS: The normal superior and inferior vena cava anatomy was found in 88.9% of patients, whereas multiple variants were found, ranging from the superior or inferior vena cava duplication, to the azygos continuation of the inferior vena cava. CONCLUSIONS: Computed tomography is a powerful tool to analyse superior and inferior vena cava anatomical variants. The knowledge and assessment of normal caval anatomy and of its anatomical variants is mandatory in the correct pre-operative planning in surgical and radiological interventions. Knowledge of caval variants is helpful in the differential diagnosis of abdominal or mediastinal masses, to avoid misdiagnosis, as well as in the screening of associated congenital pathologic conditions.

First-trimester ductus venosus velocity ratio as a marker of major cardiac defects.

OBJECTIVES: To examine ductus venosus (DV) flow in fetuses with and those without a cardiac defect and to evaluate different phases of DV flow in addition to the standard assessment of DV pulsatility index for veins (PIV) and the a-wave. METHODS: This was a retrospective study of singleton pregnancies that underwent first-trimester ultrasound screening, which included DV flow assessment, at the University of Tübingen (between 2010 and 2017) or the University of Cologne (between 2013 and 2016). The study population comprised normal fetuses and fetuses with major cardiac defects at a ratio of 10:1. For each fetus, the following parameters of the DV waveform were evaluated: qualitative assessment of the a-wave, PIV measurement and ratios of flow velocities during the S-wave (S) or D-wave (D) and the a-wave (a) or v-wave (v). Reproducibility of DV-PIV and DV flow ratios was evaluated in 30 fetuses in which the DV flow was assessed twice. RESULTS: Our study population included 480 anatomically normal fetuses and 48 with a cardiac defect. Median fetal nuchal translucency (NT) in the normal and in the affected group was 1.9 mm and 2.6 mm, respectively. In five (1.0%) of the normal and 18 (37.5%) of the affected cases, fetal NT thickness was above the 99th centile. In the normal group, the DV a-wave was reversed in 15 (3.1%) cases and the DV-PIV was above the 95th centile in 25 (5.2%). In the cases with cardiac defects, the a-wave was reversed and the DV-PIV measurement was above the 95th centile in 26 (54.2%). The reproducibility of measurement of the ratios of DV flow velocities was similar to that of the DV-PIV. Most cardiac defects were associated with an abnormal a/S or a/D ratio. If the cut-off for these two ratios was set at the 5th centile of the normal distribution, the detection rate of fetal cardiac anomalies would be 62.5%. This compares favorably with the DV-PIV, which detects 26 (54.2%) of the affected fetuses for the same threshold. CONCLUSION: In the first trimester, the a/S ratio has the potential to detect approximately 60% of congenital cardiac defects for a false-positive rate of 5%. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Dilated cerebral venous system observed in growth-restricted fetuses.

PURPOSE: The dilation of the fetal cerebral veins is a rare phenomenon that may be associated to a bad obstetric outcome, and is usually connected to antenatal thrombosis of the posterior dural venous sinuses. There are several descriptions of cerebral vein distension on magnetic resonance imaging (MRI), but all of them are detected postnatally. We present herein two cases of fetal antenatal cerebral dilation of the venous system, without any association to any sign of vein thrombosis, and a systematic review of literature regarding pathogenesis, diagnosis and outcomes associated to the antenatal detection of this condition with the use of MRI. MATERIALS AND METHODS: To identify potentially eligible studies, we searched PubMed, Scopus, Cochrane Library (all from inception to October 20th, 2016) and applied no language restrictions. RESULTS: The electronic database search provided a total of 22,843 results. After the exclusion of duplicates, manuscripts that resulted not relevant to the review based on title and abstract screening, and analysis of manuscripts eligible for full-text assessment, no papers were found related to the subject reported in the present manuscript. CONCLUSIONS: Our report adds importance to MRI as a tool in cases of complex ultrasound finding with the presence of fetal heart failure and deterioration of fetal growth, in order to improve the prognostic evaluation and patient?s counseling.

Various congenital anomalies of the inferior vena cava: review of cross-sectional imaging findings and report of a new variant.

The inferior vena cava (IVC) is an important structure receiving a large amount of venous return and is associated with various congenital disorders. Advances in diagnostic imaging and its increasing accessibility have led to an increase in the incidental detection of IVC anomalies. Congenital anomalies of the IVC are not uncommon and are occasionally critical to treatment planning. However, they are frequently overlooked in abdominal imaging. The IVC is composed of four segments (intrahepatic, suprarenal, renal, and infrarenal), and each segment arises from different embryonic structures in a complex process. Anomalies of the IVC can be classified according to the involved segment. Familiarity with the variety of IVC anomalies seen on imaging is vital for correctly diagnosing and managing patients in daily practice.

Double inferior vena cava detected by CT venography and confirmed by magnetic resonance venography: embryogenesis and literature review / Doble vena cava inferior detectada a través de venografía por tomografía computada y confirmada con venografía por resonancia magnética: embriogénesis y revisión de la literatura

A hospital based prospective study was conducted from July 2001 to July 2015 at the Department of Radiology, Jordan University Hospital, Amman, Jordan. During that period, five cases of double inferior vena cava (DIVC) were discovered among a cohort of 7722 patients (3861 men and 3861 women, 49.5±16.9 years, range 16­78 years). Cases were diagnosed by contrast-enhanced Spiral CT venography (CTV) and confirmed by turbo three-dimensional (3D) time-of-flight contrast-enhanced MR venography. The majority of patients 3166 (41 %) were referred for staging and follow-up of malignancy, postoperative complications 1777 (23 %), non-specific abdominal pain 1467 (19 %), preoperative assessment 849 (11 %) and trauma 463 (6 %). Magnetic resonance venography showed higher sensitivity, diagnostic accuracy and noninvasive modality for assessment of IVC map. MRV is a more useful, noninvasive modality for assessment of IVC map. DIVC is a common anomaly, its incidence in our study found to be 0.064 %. The incidence, literature review, embryogenesis, and importance of this anomaly are discussed. In addition, sample figures of relevant cases are provided.

En el Departamento de Radiología del Hospital de la Universidad de Jordania, Amman, Jordania, se llevó a cabo un estudio prospectivo entre el mes de julio de 2001 al mes de julio del 2015. Durante ese período se descubrieron cinco casos de vena cava inferior doble (VCID) en una cohorte de 7722 pacientes (3861 hombres y mujeres 3861, de 49,5 ± 16,9 años, con un rango de edad de 16-78 años). Los casos fueron diagnosticados por medio de venografía por tomografía computada espiral con contraste (TCV) y confirmados por medio de venografía por estudio tridimensional turbo. La mayoría de los pacientes (3166, 41 %) fueron remitidos para estadificación y seguimiento de tumores malignos. Se presentaron complicaciones postoperatorias en 1777 pacientes (23 %), dolor abdominal no especificado en 1467 (19 %), evaluación preoperatoria en 849 (11 %) y traumatismo en 463 pacientes (6 %). La venografía por resonancia magnética (RMV) mostró una mayor sensibilidad, precisión diagnóstica, y resultando no invasiva para la evaluación de la vena cava inferior (VCI). RMV es una modalidad más útil, no invasiva para la evaluación de la VCI. VCID es una anomalía frecuente, encontrándose en nuestro estudio una incidencia de 0,064 %. Además se realizó una revisión de la literatura, la embriogénesis, y la importancia de esta anomalía. También, se proporcionaron cifras de muestras de los casos relevantes.

Infrahepatic inferior caval and azygos vein formation in mammals with different degrees of mesonephric development.

Controversies regarding the development of the mammalian infrahepatic inferior caval and azygos veins arise from using topography rather than developmental origin as criteria to define venous systems and centre on veins that surround the mesonephros. We compared caudal-vein development in man with that in rodents and pigs (rudimentary and extensive mesonephric development, respectively), and used Amira 3D reconstruction and Cinema 4D-remodelling software for visualisation. The caudal cardinal veins (CCVs) were the only contributors to the inferior caval (IVC) and azygos veins. Development was comparable if temporary vessels that drain the large porcine mesonephros were taken into account. The topography of the CCVs changed concomitant with expansion of adjacent organs (lungs, meso- and metanephroi). The iliac veins arose by gradual extension of the CCVs into the caudal body region. Irrespective of the degree of mesonephric development, the infrarenal part of the IVC developed from the right CCV and the renal part from vascular sprouts of the CCVs in the mesonephros that formed 'subcardinal' veins. The azygos venous system developed from the cranial remnants of the CCVs. Temporary venous collaterals in and around the thoracic sympathetic trunk were interpreted as 'footprints' of the dorsolateral-to-ventromedial change in the local course of the intersegmental and caudal cardinal veins relative to the sympathetic trunk. Interspecies differences in timing of the same events in IVC and azygos-vein development appear to allow for proper joining of conduits for caudal venous return, whereas local changes in topography appear to accommodate efficient venous perfusion. These findings demonstrate that new systems, such as the 'supracardinal' veins, are not necessary to account for changes in the course of the main venous conduits of the embryo.

Hemodynamic studies of isolated absent ductus venosus.

OBJECTIVE: The objective of this article is to evaluate hemodynamic changes among fetuses with isolated absent ductus venosus (IADV) diagnosed by prenatal ultrasonography. PATIENTS AND METHODS: Fetuses with prenatal diagnosis of IADV were recruited and followed. Hemodynamic assessment was performed in all cases, including measurement of cardiac dimensions, shortening fraction, myocardial performance index, preload index in the inferior vena cava and the presence of venous pulsations in the umbilical vein (UV). RESULTS: Nine fetuses of IADV were assessed, including six cases with extra-hepatic UV drainage and three with intra-hepatic drainage. All fetuses with extra-hepatic UV drainage showed an elevated preload index in the inferior vena cava, venous pulsations in the UV and cardiomegaly. Of them, four had hydrops, two showed poor cardiac function and three resulted in perinatal mortality. Three cases with intra-hepatic drainage had continuous flow in the UV, normal in all hemodynamic parameters and all survived. CONCLUSION: Hemodynamic assessment of fetuses with IADV was helpful in predicting the development of hydrops and perinatal mortality. The poor prognostic factors included cardiac overload, cardiomegaly, poor myocardial performance, increased preload, the presence of venous pulsations and extra-hepatic UV drainage. © 2015 John Wiley & Sons, Ltd.

Development of the human infrahepatic inferior caval and azygos venous systems.

Differences in opinion regarding the development of the infrahepatic inferior caval and azygos venous systems in mammals centre on the contributions of 'caudal cardinal', 'subcardinal', 'supracardinal', 'medial and lateral sympathetic line' and 'sacrocardinal' veins. The disagreements appear to arise from the use of topographical position rather than developmental origin as criterion to define separate venous systems. We reinvestigated the issue in a closely spaced series of human embryos between 4 and 10 weeks of development. Structures were visualized with the Amira(®) reconstruction and Cinema4D(®) remodelling software. The vertebral level and neighbouring structures were used as topographic landmarks. The main results were that the caudal cardinal veins extended caudally from the common cardinal vein between CS11 and CS15, followed by the development of the subcardinal veins as a plexus sprouting ventrally from the caudal cardinal veins. The caudal cardinal veins adapted their course from lateral to medial relative to the laterally expanding lungs, adrenal glands, definitive kidneys, sympathetic trunk and umbilical arteries between CS15 and CS18, and then became interrupted in the part overlaying the regressing mesonephroi (Th12-L3). The caudal part of the left caudal cardinal vein then also regressed. The infrarenal part of the inferior caval vein originated from the right caudal cardinal vein, while the renal part originated from subcardinal veins. The azygos veins developed from the remaining cranial part of the caudal cardinal veins. Our data show that all parts of the inferior caval and azygos venous systems developed directly from the caudal cardinal veins or from a plexus sprouting from these veins.

The clinical anatomy of the inferior vena cava: a review of common congenital anomalies and considerations for clinicians.

Anomalies in the course and drainage of the Inferior Vena Cava (IVC) may complicate normal functioning, correct diagnosis, and therapeutic interventions within the abdomen. Development of the IVC occurs during the 4th to 8th week of gestation, and due to its developmental complexity, there are many opportunities for malformations to occur. Although most IVC anomalies are clinically silent and are usually discovered incidentally on abdominal imaging, aberrations may be responsible for formation of thrombosis, back pain, and anomalous circulation of blood to the heart. In this review, we will discuss the most common variations and abnormalities of the IVC, which include the posterior cardinal veins, the subcardinal veins, the supracardinal veins, persistent left IVC, IVC duplication, situs inversus, left retroaortic renal vein, left circumaortic renal collar, scimitar syndrome, and IVC agenesis. For each abnormality outlined above, we aim to discuss relevant embryology and potential clinical significance with regards to presentation, diagnosis, and treatment as is important for radiologists, surgeons, and clinicians in current clinical practice.

Ultrasound of the fetal veins part 1: the intrahepatic venous system.

Advances in high-resolution ultrasound combined with color Doppler and three-dimensional (3 D) rendering have contributed to an increasing understanding of the fetal venous circulation in recent years. Still the sonographic evaluation of the venous system in the fetus remains difficult. This article reviews the normal and abnormal intrahepatic venous system. Normal anatomy and abnormal findings of the umbilical vein (UV), the ductus venosus (DV), portal veins, hepatic veins and the inferior vena cava are demonstrated by grayscale, color Doppler and 3D ultrasound and explained by numerous schemes. Typical variants and abnormalities such as agenesis of the DV and portal venous system, persistence of the right UV, UV varix are explained and the clinical value of normal and abnormal Doppler findings in the DV is discussed. Many of these abnormal findings can be detected by a targeted examination of the intrahepatic vasculature with means of color Doppler.

A reference for ductus venosus blood flow at 11-13+6 weeks of gestation.

OBJECTIVE: To establish reference ranges for ductus venosus (DV) blood flow assessment obtained transabdominally at 11-13(+6) weeks of gestation. METHODS: A cross-sectional study was conducted on singleton pregnancies with a crown-rump length (CRL) ranging from 45 to 84 mm, normal fetus, and subsequent newborn birth weight appropriate for gestational age. Measurements of DV Doppler variables were performed by experienced sonographers: peak velocity during ventricular systole (S-wave) and diastole (D-wave), nadir during atrial contraction (A-wave), time-averaged maximum velocity (TAmax), pulsatility index for veins (PIV), and peak velocity index for veins (PVIV). RESULTS: A total of 304 fetuses were included. The mean CRL was 60.7 ± 7.2 mm (range: 45.9-75.5). The mean nuchal translucency measurement was 1.4 ± 0.4 mm. The S-wave, D-wave, A-wave, and TAmax values varied significantly with gestational age (p < 0.05) and regression models were constructed for each variable. The remaining variables, systolic/atrial wave ratio, preload index, PVIV, and PIV, did not vary significantly with gestational age within this CRL range. CONCLUSION: Reference ranges for DV Doppler assessment were established in normal fetuses. These ranges may be a useful tool for evaluation of anueploidy and fetal cardiac function.

Reference ranges for ductus venosus velocity ratios in pregnancies with normal outcomes.

OBJECTIVES: The purpose of this study was to establish reference ranges for ductus venosus velocity ratios. METHODS: Singleton pregnancies from 11 to 38 weeks with exactly established gestational ages (GAs) were recruited for the study. Pregnancies with fetal anomalies, growth abnormalities, maternal medical complications, stillbirth, birth weight below the 10th or above the 90th percentile, and neonatal anomalies were excluded. The ductus venosus pulsatility index for veins (PIV) and velocity ratios (S/v, S/D, v/D, S/a, v/a, and D/a, where S indicates ventricular systole [s-wave], v, ventricular end-systolic relaxation [v-descent], D, passive diastolic ventricular filling [D-wave], and a, active ventricular filling during atrial systole [a-wave]) were calculated. Separate regression models were fitted to estimate the mean and standard deviation at each GA for each ratio. RESULTS: A total of 902 velocity wave ratios and ductus venosus PIVs were used for reference ranges. The S/v, S/D, and v/D ratios were not changed with GA (P > .05 for all). The PIV and S/a, v/a, and D/a ratios were reduced with GA (P < .0001 for all). Significant reductions in the means and standard deviations of the PIV and S/a, v/a, and D/a ratios were observed between 17 and 18 weeks' gestation. Therefore, nomograms were separately created between 11 and 17 weeks and 18 and 38 weeks. CONCLUSIONS: We created reference ranges for ductus venosus velocity ratios between 11 and 38 weeks' gestation in normal pregnancies. These reference ranges may prove beneficial for evaluation of fetal conditions that are associated with cardiovascular abnormalities.

Ductus venosus closure results in transient portal hypertension--is this the silent trigger for necrotizing enterocolitis?

INTRODUCTION: The etiology of necrotizing enterocolitis (NEC) remains elusive and no definite trigger has been identified. There are no studies to date examining the potential role of closure of the ductus venosus (DV), its effect on increasing portal venous pressure (PVP) and its association to mesenteric venous ischemia in the development of NEC. Our aim was to develop an animal model to examine this physiology. METHODS: Fifteen near-term lambs were used. The DV was occluded in experimental animals by a balloon tip catheter, while the sham controls underwent catheterization without DV occlusion. Vital signs and PVP were monitored for 4h, followed by intestinal biopsy. RESULTS: The experimental group (n=5) demonstrated a significant increase in PVP following DV occlusion (11.87 mm Hg [95% CI: 11.40-12.34]), compared to controls (8.95 mm Hg [95% CI: 8.34-9.56]) (F=12.16, p=0.001). Histology of the terminal ileum showed vacuolar degeneration, indicative of reversible cellular damage in the experimental group. CONCLUSIONS: We demonstrate that DV closure in the neonatal lamb leads to transient portal hypertension which is associated with cellular damage and inflammatory changes of the intestinal mucosa. Additional studies will be necessary to determine if the transient portal hypertension following DV closure leads to clinically apparent intestinal ischemia and NEC.

[Computerized three-dimensional reconstruction of the retrohepatic segment of inferior vena cava of a 20 mm human embryo]. / Reconstruction tridimensionnelle informatisée du segment rétrohépatique de la veine cave inférieure d'un embryon humain de 20mm.

The subdiaphragmatic venous drainage of the embryo is provided by the two caudal cardinal veins to which is added the subcardinal vein system, draining the mesonephros, the perispinal supracardinal veins and the umbilical and vitelline venous system. The anastomosis of certain segments of the embryonic venous structures and the disappearance of others are at the origin of the inferior vena cava. Since the 19th century, three-dimensional reconstruction of solid models from histological sections were developed. At present, the development of computerized three-dimensional reconstruction techniques allowed to operate a multitude of techniques of image processing and modeling in space. Three-dimensional reconstruction is a tool for teaching and research very useful in embryological studies because of the obvious difficulty of dissection and the necessity of introducing time as the fourth dimension in the study of organogenesis. This method represents a promising alternative compared to previous three-dimensional reconstruction techniques including Born technique. The aim of our work was to create a three-dimensional computer reconstruction of the retrohepatic segment of the inferior vena cava of a 20mm embryo from the embryo collection of Saints-Pères institute of anatomy (Paris Descartes university, Paris, France) to specify the path relative to the liver and initiate a series of computerized three-dimensional reconstruction that will follow the evolution of this segment of the inferior vena cava and this in a pedagogical and morphological research introducing the time as the fourth dimension.

Missing ductus venosus: a case report.

BACKGROUND: The ductus venosus is a short vessel, present in the newborn infant on the dorsal surface of the liver, connecting the portal and umbilical circulation with the inferior vena cava. Agenesis of the duct is a rare anomaly. CASE: A 28-year-old woman was referred to our department for the first trimester ultrasound evaluation. Detailed scanning revealed agenesis of the duct. Fetal echocardiography showed cardiac disproportion at the level of the ventricles. CONCLUSION: Agenesis of the duct can be related to either cardiac or congenital abnormalities.

Evolution of congenital malformations of the umbilical-portal-hepatic venous system.

OBJECTIVE: The objective of this study is to describe the evolution of 8 cases of congenital malformations of the umbilical-portal-hepatic venous system diagnosed before the first month of life. MATERIALS AND METHODS: All cases of congenital malformation of the portal and hepatic venous system diagnosed prenatally or during the first month of life in our institution were systematically reviewed since November 2000. Clinical features, imaging, and anatomical findings were reviewed, focusing primarily on clinical and radiologic evolution. RESULTS: Eight cases of congenital malformation of the umbilical-portal-hepatic venous system were studied. Fifty percent of these malformations were diagnosed prenatally. We report 4 portosystemic shunts. Three involuted spontaneously, and the fourth one required surgical treatment. We report a variation of the usual anatomy of portal and hepatic veins that remained asymptomatic, an aneurysmal dilatation of a vitelline vein causing portal vein thrombosis that needed prompt surgical treatment with good result, a complex portal and hepatic venous malformation treated operatively, and a persistent right umbilical vein that remained asymptomatic. CONCLUSION: Prenatal diagnosis of malformations of the umbilical-portal-hepatic venous network is uncommon. Little is known about the postnatal prognosis. Clinical, biologic, and radiologic follow-up by ultrasonography is essential to distinguish pathologic situations from normal anatomical variants.