Which radiographic sign is associated with transposition of the great arteries?

• A. Egg-on-a-string
• B. Boot-shaped heart
• C. Snowman sign
• D. Cupped heart

Answer: (A)

The main idea is recognizing the chest X-ray clue that points to transposition of the great arteries. In this condition, the aorta arises from the right ventricle and the pulmonary artery from the left ventricle, causing parallel rather than serial circulations. On a frontal chest radiograph this often creates an egg-on-a-string appearance: a round, globular cardiac silhouette (the egg) sitting on a narrow, slender mediastinal column (the string). This radiographic clue helps identify TGA in newborns who are cyanotic, guiding urgent confirmation and management.

Other signs reflect different heart conditions, so they don’t fit TGA. A boot-shaped heart is classic for Tetralogy of Fallot; the snowman sign is associated with total anomalous pulmonary venous return (supracardiac type); cupped heart is not a typical feature of TGA and points to other pathologies.