Cardiomegaly chest x ray


 * Associate Editor in Chief:

Chest X Ray

 * Cardiomgaly is traditionally defined as an increase in the cardiothoracic ratio to be > 0.5 on a PA film. To calculate the thoracic ratio, the width of the cardiac silhouette is divided by the width of the entire thoracic cage.
 * If the heart is viewed on an AP film, the heart can appear to be artificially enlarged because the X ray beam moves from anterior to posterior direction and therefore the heart which lies anterior is magnified.
 * Postero Anterior (PA) Projection: adult heart is 12 cm from base to apex and 8-9 cm in transverse direction
 * Lateral Projection: The adult heart is 6 cm in the Antero Posterior (AP) direction

X-ray findings for left ventricular enlargement

 * Left heart border is displaced leftward, inferiorly, or posteriorly.
 * Rounding of the cardiac apex







X-ray findings for left atrial enlargement

 * Double density sign: Occur when the right side of the left atrium pushes into the adjacent lung.
 * Convex left atria appendage: usually reflect prior rheumatic heart disease
 * Splaying of the carina
 * Posterior displacement of the left main stem bronchus on lateral radiograph
 * Superior displacement of the left main stem bronchus on frontal view
 * Posterior displacement of a barium filled esophagus





X-ray findings for right ventricular enlargement

 * Frontal view


 * Rounded left heart border
 * Uplifted apex


 * Lateral view
 * Filling of the retrosternal space
 * Rotation of the heart posteriorly

X-ray findings for right atrial enlargement

 * On a frontal view, the right atrium is visible because of its interface with the right middle lobe.
 * Subtle and moderate right atrial enlargement is not accurately determined on plain films because there is normal variability in the shape of the right atrium.