Cardiothoracic ratio
Updates to Article Attributes
The cardiothoracic ratio (CTR) aids in the detection ofcardiomegaly, or more broadly,
Radiographic features
ItThe 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. A normal measurement should be less than 0<0.5.
Related pathology
It should be noted however that this measurement is a coarse tool, and if clinical concern existsmarker of disease 4. If the patient is symptomatic then echocardiography is required. It will be not only able to assess cardiac function (cardiac size being a surrogate marker but the yield of function) but also exclude other causes of enlargement of the cardiac silhouette (e.g. pericardial effusion)
In some situations, the an increased cardiothoracic ratio on a PA radiograph may just result from a prominent epicardial fat pad and due to expiration rather than from due to cardiomegaly.
-<p>The <strong>cardiothoracic ratio</strong> aids in the detection of <a href="/articles/cardiomegaly">cardiomegaly</a>, or more broadly, <a href="/articles/enlargement-of-the-cardiac-silhouette">enlargement of the cardiac silhouette</a>. </p><p>It is measured on a PA chest x-ray, and is the ratio of:</p><ol>-<li>maximal horizontal cardiac diameter</li>-<li>maximal horizontal thoracic diameter (inner edge of ribs / edge of pleura)</li>-</ol><p>A normal measurement should be less than 0.5. </p><p>It should be noted however that this is a coarse tool, and if clinical concern exists then echocardiography is required. It will be not only able to assess cardiac function (cardiac size being a surrogate marker of function) but also exclude other causes of enlargement of the cardiac silhouette (e.g. <a href="/articles/pericardial-effusion">pericardial effusion</a>).</p><p>In some situations, the an increased cardiothoracic ratio on a PA radiograph may just result from a <a href="/articles/prominent-epicardial-fat-pad">prominent epicardial fat pad</a> and due to expiration rather than from due 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 cardiomegaly but can be due to other processes such as <a href="/articles/pericardial-effusion">pericardial effusion</a>. </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, the an increased cardiothoracic ratio on a PA radiograph may just result from a <a href="/articles/prominent-epicardial-fat-pad">prominent epicardial fat pad</a> and due to <a href="/articles/expiratory-chest-radiograph">expiration</a> rather than from due to cardiomegaly.</p>
References changed:
- 3. Echocardiography is not indicated for an enlarged cardiothoracic ratio. British Journal of Cardiology. 2013; . <a href="http://dx.doi.org/10.5837/bjc.2013.30">doi:10.5837/bjc.2013.30</a><span class="auto"></span>
- 4. Fonseca C, Mota T, Morais H et-al. The value of the electrocardiogram and chest X-ray for confirming or refuting a suspected diagnosis of heart failure in the community. Eur. J. Heart Fail. 2004;6 (6): 807-12, 821-2. <a href="http://dx.doi.org/10.1016/j.ejheart.2004.09.004">doi:10.1016/j.ejheart.2004.09.004</a> - <a href="http://www.ncbi.nlm.nih.gov/pubmed/15542421">Pubmed citation</a><span class="auto"></span>
Sections changed:
- Approach
Image 1 Annotated image (Figure 2) ( update )
Image 2 Annotated image (Figure 1) ( update )
Image 3 X-ray (Frontal) ( create )
Image 4 X-ray (Frontal) ( create )
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