Pericardial effusion CT
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American Roentgen Ray Society Images of Pericardial effusion CT |
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Risk calculators and risk factors for Pericardial effusion CT |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor-In-Chief: Cafer Zorkun, M.D., Ph.D. [2]; Varun Kumar, M.B.B.S.
Overview
Computed tomography is an effective diagnostic tool in cases of pericardial effusion as it helps us to narrow down on the etiology by determining the amount and nature of the pericardial fluid. CT is very useful especially in identifying hemorrhagic effusions or clots within the pericardium. A pericardial effusion is often incidentally noted on CT scans obtained for other indications.
Computed Tomography
- Both MRI and CT have an advantage over echocardiography insofar as they can detect loculated effusions as well as generalized effusions[1] [2].
- Computed tomography is superior to MRI in assessing pericardial calcification.
- If the fluid is free-flowing and not loculated, it will first accumulate at the posterior lateral aspect of the left ventricle in the supine position.
- It can be hard to differentiate a small pericardial effusion from pericardial thickening of about 4 mm since both entities generate a similar signal.
- In the presence of acute pericarditis, the pericardium can generate an intermediate signal intensity and may enhance after gadolinium administration.
- Estimation of the amount of fluid is possible to a limited extent based on the overall thickness of the crescent of fluid.
- Hemorrhagic effusions can be differentiated from a transudate or an exudate based on signal characteristics (high signal on T1-weighted images) or density (high-density clot on CT). Pulsation artifacts may cause local areas of low signal in a hemorrhagic effusion.
- CT attenuation measurements also enable the initial characterization of pericardial fluid.
- A fluid collection with attenuation close to that of water is likely to be a simple effusion.
- Attenuation greater than that of water suggests malignancy, hemopericardium, purulent exudate, or effusion associated with hypothyroidism.
- Pericardial effusions with low attenuation also have been reported in cases of chylopericardium.
