Left aortic arch - right descending aorta - right ductus arteriosus (encircling aortic arch). A rare "vascular ring" malformation.

Abnormalities of the aortic arch which are responsible for tracheobronchial compression are well known. This case demonstrates the value of magnetic resonance imaging (MRI) for diagnosis and suggests that recurrent respiratory symptoms should evoke these abnormalities in infancy. Case report. - The authors report a very rare malformation of the aortic arch formed by encircling aortic arch, with left aortic arch, right descending aorta and right ligamentum arteriosum. It was revealed by airway disorders due to the compression of tracheobronchial axis by the ligamentum arterosium. Section of the ligamentum permitted suppression of obstruction. The diagnosis of these abnormalities is usually established by means of oesophagogram, tracheobronchial endoscopy, angiography and MRI. Conclusion. - In this case, MRI gave a better picture than angiography. Sections of the ligamentum arteriosum are sometimes ineffective when compression is due to the aorta itself Aortic uncrossing, a more complex operation, is then necessary. (C) 1998, Elsevier, Paris.