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Question:
What is a prominent cardiac silhouette and what is CTR?
I did chest x-ray and the result said, "Cardiac silhouette appears prominent and the CTR is approximately 57 percent." What does this mean?
submitted by Kavugho from RSA on 10/17/2014
Answer:
by Texas Heart Institute cardiologist, Benjamin Y. Cheong, MD
The cardiothoracic ratio (CTR) is a chest x-ray measurement (in a properly perform PA chest x-ray). It is defined as follows:
maximum diameter of the heart / maximum diameter of the chest
A normal measurement should be less than 0.5. A number > 0.5 may suggest enlargement of the heart chamber size.
However, there are also other factors that could affect this measurement, such as the degree of breath taken during the CXR, or whether the CXR was taken during "breath-in" or "breath-out" phases, to name a few examples.
One can discuss with your ordering doctor regarding this finding (he/she can speak to the Radiologist about the interpretation). Also of interest is whether the CXR was taken due to concern for a chest infection versus shortness of breath? An echocardiogram, which is a heart ultrasound scan, will be able to measure the heart size accurately.
Your doctor will be able to guide you depending on your clinical symptoms; not infrequently, the above finding may be of no clinical significance.
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Updated October 2014
