Multi-modality evaluation of the abnormalities of the aortic arches in children: techniques and imaging spectrum with emphasis on MRI

The failure of embryonic vascular arches to fuse and regress in the usual manner during the formation of the aortic arch, pulmonary arteries and ductus arteriosus can cause a wide spectrum of vascular congenital abnormalities of the aortic arch and its branches. These abnormal vascular structures may cause variable compression of the trachea and/or oesophagus with symptoms ranging from none to severe stridor, dyspnoea, dysphagia and cyanosis. Diagnosis and possible treatment of affected patients require multiple imaging modalities. In the majority of cases, the underlying malformation can be detected by chest radiography and barium oesophagography, visualizing the location of the aortic arch and the presence of anomalous compressions of the trachea and/or oesophagus. However, in most cases the exact configuration of the vascular abnormality cannot be fully defined with conventional radiology alone. MRI is fundamental for evaluation of the thoracic vessels. Not only is it non-invasive, but it can also provide large-field-of-view images in any number of planes with three-dimensional reconstruction, adding valuable information about exact vascular configuration, tracheobronchial compression and brachiocephalic vessel branching. The aim of this review is to describe the imaging findings in children affected with special emphasis on MRI.