F. Gámez

Fetal thymus size in uncomplicated twin and singleton pregnancies

The main objective of this study was to determine whether fetal thymic measurements could be obtained in twins, with a secondary goal to determine whether thymic measurements from uncomplicated singleton and twin pregnancies are comparable.

Second-trimester fetal aberrant right subclavian artery: original study, systematic review and meta-analysis of performance in detection of Down syndrome

First, to estimate the prevalence of fetal aberrant right subclavian artery (ARSA) in our population and its association with Down syndrome. Second, to determine the feasibility of ultrasound to visualize ARSA in the three planes. Finally, to carry out a systematic review of the literature on the performance of second‐trimester ARSA to identify fetuses with Down syndrome.

Sonographic thymic measurements in Down syndrome fetuses.

Children with Down syndrome (DS) can have hypoplastic thymuses with an impaired capacity to liberate newly generated T cells. We sought to determine if the size of the thymus in DS fetuses is different from control fetuses.

Perinatal outcome after ultrasound prenatal diagnosis of persistent right umbilical vein

OBJECTIVE Our aim was to describe ultrasound findings and perinatal outcome after prenatal diagnosis of persistent right umbilical vein (PRUV). STUDY DESIGN We performed a retrospective analysis of fetuses with an ultrasound-based prenatal diagnosis of PRUV on record at 2 tertiary centers in Madrid, Spain. We describe clinical, maternal, fetal and perinatal variables for all cases. RESULTS A total of 20,426 fetuses were delivered between the study centers. We detected 22 cases (0.1%) of PRUV. The male-to-female ratio was 1:1. All cases were intrahepatic type and diagnosed during the second and third trimesters (median, 21 weeks; IQR, 20-29 weeks). Doppler ultrasound revealed normal flow in the ductus venosus in all cases. Nine fetuses (40.9%) had additional ultrasound anomalies but no chromosomal abnormalities. Cardiovascular malformations were the most frequently associated congenital anomalies (4/9), followed by neurological malformations (2/9). In 5 of the cases with no concomitant anomalies, the weight of the newborn was below the tenth percentile for gestational age. Gestational development was normal for the remaining newborns. Delivery was unremarkable, and post-natal evolution was favorable. CONCLUSION Our results point to a potential association between PRUV and other fetal malformations and a very low rate of chromosomal abnormalities. Prenatal diagnosis of PRUV should be followed by detailed anatomical evaluation and echocardiography in order to rule out other structural malformations. The indication for a fetal karyotype study must be made on an individual basis considering PRUV type and other ultrasound findings.

Fetal Aortic Arch Anomalies Key Sonographic Views for Their Differential Diagnosis and Clinical Implications Using the Cardiovascular System Sonographic Evaluation Protocol

Aortic arch anomalies are present in 1% to 2% of the general population and are commonly associated with congenital heart disease, chromosomal defects, and tracheaesophageal compression in postnatal life. The sonographically based detection of aortic arch anomalies lies in the 3‐vessel and trachea view. Although highly sensitive, this view alone does not allow identification of the aortic arch branching pattern, which prevents an accurate diagnosis. The systematic addition of a subclavian artery view as part of a standardized procedure may be useful in the differential diagnosis of these conditions. We describe the sonographic assessment of fetal aortic arch anomalies by combining 2 fetal transverse views: the 3‐vessel and trachea view and the subclavian artery view, which are included in the cardiovascular system sonographic evaluation protocol. We also review the sonographic findings and the clinical implications of fetal aortic arch anomalies.

Comparison of measurements of the transverse diameter and perimeter of the fetal thymus obtained by magnetic resonance and ultrasound imaging

To compare measurements of the fetal thymus obtained by magnetic resonance imaging (MRI) and ultrasound (US).

Coronal view as a complementary ultrasound approach for prenatal diagnosis of aberrant right subclavian artery

Aberrant right subclavian artery (ARSA) is associated with chromosomal abnormalities, mainly Down syndrome, and congenital heart disease1–5. ARSA is caused by abnormal regression of the primitive right aortic arch between the right subclavian artery and the right common carotid artery. As a result, the aortic arch branches into four arteries instead of three, and the ARSA originates distal to the left subclavian artery at the level of the aortic isthmus. ARSA follows an oblique course behind the trachea and esophagus to reach the right arm. In 2005, Chaoui et al.2 described the methodology for assessment of fetal ARSA in the transverse three vessels and trachea view, in which the anomalous origin of ARSA, close to the ductus arteriosus, and its retrotracheal course can be visualized (Figures 1a and c). This group subsequently showed how to visualize fetal ARSA in a longitudinal view6, in which the artery arises as a fourth and distal vessel from the aortic arch; however, in this view the retrotracheal course is not identifiable. As Quarello and Carvalho7 remarked, although several anatomical variations can manifest as an aortic arch with four vessels in the longitudinal view, in cases in which ARSA originates anteriorly from the aortic arch, visualization of four supra-aortic vessels is not possible. We illustrate how this vessel can be visualized in the coronal plane. In order to assess ARSA, we obtain a coronal view of the fetal thorax, posterior to the trachea and anterior to the spine, until we are able to see the thoracic descending aorta. Highly sensitive color Doppler with a low velocity range (10–15 cm/s) shows ARSA as a vessel arising from the descending aorta at the level of the aortic isthmus and following an S-shaped course towards the right clavicle and shoulder (Figures 1b and c). This view has the advantage of providing visualization of the origin and course of the anomalous artery in the same plane. This view can also facilitate evaluation in cases in which the origin of ARSA is not in its most common position, such as ARSA originating anteriorly from the aortic arch or very distal to the left subclavian artery. It is important not to confuse ARSA with the azygos vein and its anastomosis with the superior vena cava. In the coronal view, the azygos vein courses parallel to the right side of the aorta, while ARSA arises from the aorta and follows an oblique course to reach the right arm. Pulsed Doppler interrogation is recommended to distinguish ARSA from the azygos vein in this region. In summary, fetal ARSA can be viewed in the coronal plane using ultrasonography. This approach shows both the anomalous origin of the artery and its S-shaped course to the right shoulder. Although the detection of ARSA is possible in a coronal view, it should be confirmed in the three vessels and trachea view.

Cardiovascular System Sonographic Evaluation Algorithm A New Sonographic Algorithm for Evaluation of the Fetal Cardiovascular System in the Second Trimester

To evaluate the reproducibility and feasibility of the new cardiovascular system sonographic evaluation algorithm for studying the extended fetal cardiovascular system, including the portal, thymic, and supra‐aortic areas, in the second trimester of pregnancy (19–22 weeks).

Prenatal Sonographic Features of a Double Aortic Arch Literature Review and Perinatal Management

A double aortic arch is a relatively uncommon anomaly occasionally associated with congenital heart disease or the chromosome 22q11 deletion. We report a case of prenatal diagnosis of a double aortic arch in which the sonographic features in the 3‐vessel and trachea view are highlighted. A PubMed‐based search was made to retrieve all cases of prenatal diagnosis of double aortic arch. A total of 13 articles and 35 cases were found. The average gestational age at diagnosis was 29 weeks. Six cases had associated cardiac anomalies. Only 1 case had the 22q11 deletion, showing extracardiac anomalies without cardiac defect. The postnatal evolution was characterized by symptoms of tracheoesophageal compression in 72.4% of the cases. Detection of a double aortic arch should be followed by a thorough fetal scan and echocardiography, and a chromosomal study should be considered when the sonographic findings are consistent with the 22q11 deletion.

Prenatal Diagnosis of an Aortopulmonary Window With an Interrupted Aortic Arch

A prenatal aortopulmonary window with an interrupted aortic arch was detected in a 22‐week‐old fetus. The 3‐vessel and trachea view showed a communication between the ascending aorta and the pulmonary artery. Early postnatal surgery was successful. A PubMed‐based search identified all cases of prenatal aortopulmonary windows between 2002 and 2015. Nine articles were identified. The average gestational age at diagnosis was 28 weeks (range, 22–33 weeks). The most frequent aortopulmonary window was type I (40%). All cases were associated with congenital heart defects, mainly an interrupted aortic arch (50%). No chromosomal or extracardiac abnormalities were seen. Prenatal echocardiography is useful for early diagnosis of an aortopulmonary window. The prognosis depends on the time of surgery and the nature of the associated anomalies.