What is the normal cardiothoracic ratio in children?
"The cardiac silhouette occupies 50-55% of the chest width. Cardiomegaly is present when the cardiothoracic (CT) ratio is more than 55%".The 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%).(Refer: Nelson's Textbook of Pediatrics, SAE, 1st edition, pg no. 2170)
30-35%
40-45%
50-55%
60-65%
All India exam