What is the cardiothoracic ratio in children is -: (A) 30-35%, (B) 40-45%, (C) 50-55%, (D) 60-65%
Answer is C. “The cardiac silhouette occupies 50-55% of the chest width.
Cardiomegaly is present when the cardiothoracic (CT) ratio is more than 55%” he CTR is measured on a PA chest x-ray and is the ratio of maximal horizontal cardiac diameter to maximal horizontal thoracic diameter (inner edge of ribs / edge of pleura).
A normal measurement should be <0.5(50%).