Cardiothoracic ratio
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
The cardiothoracic ratio is the calculated by measuring the transverse diameter of the heart on a posterior / anterior chest X ray x-ray examination and dividing it by the diameter of the thoracic cage. A value > 0.5 or one half is consistent with enlargement of the heart or [cardiomegaly]]."[1]