Cardiothoracic ratio
Updates to Article Attributes
The cardiothoracic ratio (CTR) aids in the detection of enlargement of the cardiac silhouette, which is most commonly from cardiomegaly but can be due to other processes such as pericardial effusion.
Terminology
Some report CTR as a percentage, however this is strictly incorrect, as it is a ratio.
Radiographic features
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.
Related pathology
It should be noted that this measurement is a coarse marker of disease 4. If the patient is symptomatic then echocardiography is required but the yield of echocardiography is low if performed just for an increased CTR 3.
In somethis situations, an increased cardiothoracic cardiothoracic ratio is more than 0.5 on a PA radiograph may be a result of , but heart is normal:
- a prominent epicardial fat pad
and/or - due to expiration
rather than cardiomegaly. - Pregnancy
- Obesity
- Ascites
- Pectus excavatum
- straight back syndrome
-<p>The <strong>cardiothoracic ratio</strong> (<strong>CTR</strong>) aids in the detection of <a href="/articles/enlargement-of-the-cardiac-silhouette">enlargement of the cardiac silhouette</a>, which is most commonly from <a href="/articles/cardiomegaly">cardiomegaly</a> but can be due to other processes such as <a href="/articles/pericardial-effusion">pericardial effusion</a>. </p><h4>Terminology</h4><p>Some report CTR as a percentage, however this is strictly incorrect, as it is a ratio.</p><h4>Radiographic features</h4><p>The CTR is measured on a PA <a href="/articles/chest-radiograph">chest x-ray</a>, 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.</p><h4>Related pathology</h4><p>It should be noted that this measurement is a coarse marker of disease <sup>4</sup>. If the patient is symptomatic then echocardiography is required but the yield of echocardiography is low if performed just for an increased CTR <sup>3</sup>.</p><p>In some situations, an increased cardiothoracic ratio on a PA radiograph may be a result of a prominent <a href="/articles/epicardial-fat-pads">epicardial fat pad</a> and/or due to <a href="/articles/chest-expiratory-view-1">expiration</a> rather than cardiomegaly.</p>- +<p>The <strong>cardiothoracic ratio</strong> (<strong>CTR</strong>) aids in the detection of <a href="/articles/enlargement-of-the-cardiac-silhouette">enlargement of the cardiac silhouette</a>, which is most commonly from <a href="/articles/cardiomegaly">cardiomegaly</a> but can be due to other processes such as <a href="/articles/pericardial-effusion">pericardial effusion</a>. </p><h4>Terminology</h4><p>Some report CTR as a percentage, however this is strictly incorrect, as it is a ratio.</p><h4>Radiographic features</h4><p>The CTR is measured on a PA <a href="/articles/chest-radiograph">chest x-ray</a>, 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.</p><h4>Related pathology</h4><p>It should be noted that this measurement is a coarse marker of disease <sup>4</sup>. If the patient is symptomatic then echocardiography is required but the yield of echocardiography is low if performed just for an increased CTR <sup>3</sup>.</p><p>In this situations, cardiothoracic ratio is more than 0.5 on a PA radiograph, but heart is normal:</p><ul>
- +<li>a prominent <a href="/articles/epicardial-fat-pads">epicardial fat pad</a>
- +</li>
- +<li>due to <a href="/articles/chest-expiratory-view-1">expiration</a> </li>
- +<li>Pregnancy</li>
- +<li>Obesity</li>
- +<li><a title="Ascites" href="/articles/ascites">Ascites</a></li>
- +<li><a title="Pectus excavatum" href="/articles/pectus-excavatum">Pectus excavatum</a></li>
- +<li><a title="Straight back syndrome" href="/articles/straight-back-syndrome">straight back syndrome</a></li>
- +</ul><p> </p><p> </p>