![]() 10), 11) At present, echocardiography, MRI, and CT angiography are the main modalities used to detect and evaluate aortic arch variants and anomalies.ĬT provides high spatial resolution of the anatomy of the vessels and surrounding structures. 9) Classical modalities such as barium esophagram and catheter angiography are not frequently used as first-line diagnostic tools because they are difficult to use in pediatric patients and provide only two-dimensional (2D) information. Imaging techniques available for diagnosing arch anomalies include barium esophagram, echocardiography, CT angiography, MRI, and catheter angiography. IMAGING MODALITIES FOR EVALUATION OF THE AORTIC ARCH AND ASSOCIATED STRUCTURES The primitive sixth arch persists as a segment of the pulmonary arteries and ductus arteriosus. The third arch becomes the common carotid and proximal internal carotid arteries, while the fourth arch forms the definitive adult aortic arch. 6) After regression of some arches, the remnant third, fourth, and sixth primitive arch give rise to mature great vessels. The primitive fifth aortic arch usually regresses however, it may rarely persist as a double barrel aorta. 5) The primitive first and second arches regress first and the remnant portions become the maxillary, hyoid, and stapedial arteries. This embryologic model was originally proposed in the classic Rathke diagram ( Figure 1). These primitive arches appear individually, regress, and eventually remodel and transform into portions of the great vessel system, including the aortic arch, arch branches, ductus arteriosus, and proximal segments of the pulmonary arteries. 4) The great vessel system, including the aortic arch, arises from six pairs of pharyngeal arch arteries, each connecting the dorsal and ventral primitive aortae. The development of the great vessel system starts at around 3 weeks of gestation and is mostly completed by 8 weeks of gestation in humans. In this article, we review the classification of aortic arch anomalies with a focus on embryologic development and clinical features. 3) Various modalities can be used for detailed evaluation of the anatomy of the aortic arch and the hemodynamics of the arch vessels, which is necessary for planning surgery or endovascular intervention. Imaging studies are critical for detection and diagnosis of these anomalies. 2) Additionally, association of arch anomalies with congenital heart disease and chromosomal/genetic abnormalities must be considered. From a clinical perspective, aortic arch anomalies can be present without definite symptoms or may be accompanied by various symptoms, including difficulty breathing or swallowing. 1) Advances in imaging modalities and increased use of cross-sectional imaging, including multidetector computed tomography (CT) and magnetic resonance imaging (MRI), have resulted in frequent incidental detection of these malformations. ![]() In this review, we describe the embryological development of the thoracic aorta and discuss variations and anomalies of the aortic arch along with their clinical implications.Ĭongenital anomalies and variants of the aortic arch encompass a wide range of aortic arch malformations that result from interrupted embryogenesis of the branchial arches. For accurate diagnosis and precise evaluation of aortic arch anomalies, cross-sectional imaging modalities, such as multidetector CT or magnetic resonance imaging, play an important role by providing three-dimensional reconstructed images. Understanding the embryological development of the aortic arch aids in the classification of various subtypes of aortic arch anomalies and variants. Thus, radiologists and clinicians should be aware of the classification of aortic arch anomalies and carefully look for imaging features associated with a high risk of clinical symptoms. The widespread use of multidetector computed tomography (CT) in clinical practice has resulted in incidental detection of several variations of the aortic arch in adults. Some of these may be accompanied by other congenital heart diseases or chromosomal anomalies. There is a wide spectrum of congenital anomalies or variations of the aortic arch, ranging from non-symptomatic variations that are mostly detected incidentally to clinically symptomatic variations that cause severe respiratory distress or esophageal compression.
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