X-Ray Appearance in D-TGA

X-ray appearance in D-TGA

Egg on side appearance is the classical appearance of the cardiac shadow on X-ray chest PA view in dextro transposition of great arteries [1]. The anteroposterior relationship of aorta and pulmonary artery and thymic hypoplasia contribute to the narrow pedicle in infancy in dextro transposition of great arteries. Some also call it ‘egg on string’ appearance to account for the narrow pedicle.

In a case reported by Varal et al, a baby admitted to neonatal intensive care unit with severe respiratory distress, cyanosis and a short systolic murmur had X-ray chest showing “egg on a string” sign [2]. Emergency echocardiography and cardiac catheterisation confirmed the diagnosis of D-TGA. Prostaglandin E1 infusion to maintain ductal patency followed by arterial switch operation was planned. Authors mentioned that the “egg on a string” sign may be seen on chest X-ray in around one third of patients with D-TGA.

It may be noted the X-ray appearance in congenitally corrected transposition is entirely different from that of dextro transposition of great arteries. Congenitally corrected transposition is also called levo transposition of great arteries because of the levoposed aorta. Levo posed aorta is seen as a bulge along the left upper border of the heart [3].

References

1. Michael W. Szymanski; Sheila M. Moore; Stacy M. Kritzmire; Amandeep Goyal. Transposition Of The Great Arteries. StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan.
2. Ipek Guney Varal, Pelin Dogan. Egg on a String Sign. Pan Afr Med J. 2018 Oct 3;31:79.
3. J Somerville, V Grech. The Chest X-Ray in Congenital Heart Disease 2. Images Paediatr Cardiol. 2010 Jan;12(1):1-8.