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

Abstract

Coronal view as a complementary ultrasound approach for prenatal diagnosis of aberrant right subclavian arteryAberrant right subclavian artery (ARSA) is associated with chromosomal abnormalities, mainly Down syndrome, and congenital heart disease 1 -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 view 6 , 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 Carvalho 7 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.

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

“…(Figure d, Videoclip S2). These complementary approaches, together with the use of pulsed‐wave Doppler, help to confirm the diagnosis of ARSA and, especially in the coronal view, to differentiate it from neighboring vessels.…”

“…For our second objective, when ARSA was detected, images of this vessel were obtained in the longitudinal and coronal views when possible, following the methods described by Chaoui et al 9 (Figure 1c) and De León-Luis et al (Figure 1d, Videoclip S2) 10 . These complementary approaches, together with the use of pulsed-wave Doppler, help to confirm the diagnosis of ARSA and, especially in the coronal view, to differentiate it from neighboring vessels 9,10 .…”

“…Interest in prenatal assessment of fetal aberrant right subclavian artery (ARSA) has increased because of the known association between this condition and Down syndrome and other congenital anomalies. Ultrasound assessment of ARSA is performed in the axial plane at the level of the three vessels and trachea view, although it can also be observed in the longitudinal and coronal planes (Figure ); however, feasibility in non‐axial planes has not been described.…”

Prenatal diagnosis of aberrant right subclavian artery in an unselected population

“…In order to assess ARSA, we obtained a coronal view of the fetal thorax, posterior to the trachea and anterior to the spine, until we could see the thoracic descending aorta. Color Doppler ultrasonography showed ARSA as a vessel arising from the descending aorta at the level of the aortic isthmus [11]. ARSA then followed an oblique course towards the right clavicle and shoulder (Fig.…”

Assessesment of Subclavian Arteries: Usefulness of Coronal View in Prenatal Ultrasound Diagnosis

“…This view, as described by Leon, allow us to distinguish ARSA from azygous draining into the right superior vena cava and thus avoid false positive [17] (Figure 1). …”