What can a chest x-ray measure?
A chest x-ray can be used to figure out your cardiothoracic ratio (CTR), which compares the maximum diameter of your heart to the maximum diameter of your chest. A CTR less than 0.5 is normal, whereas a higher CTR could indicate that some part of your heart is enlarged.
Your breathing can affect these measurements, so the technician may ask you to hold your breath at certain times during the x-ray.
If the results of your x-ray aren’t clear, doctors may order an echocardiogram to more precisely measure the size of your heart.