Cardiac Tamponade: CT Findings

CT findings of cardiac tamponade can be nonspecific. However, when seen together in the setting of a large pericardial effusion, the following should strongly suggest the diagnosis:

• Distention of the superior vena cava: ≥ diameter of the adjacent thoracic aorta.
• Distention of the inferior vena cava: ≥ twice the diameter of the adjacent abdominal aorta. Distension of the hepatic and renal veins can also be seen.
• Periportal edema: Can also be seen with chronic congestive heart failure, among other conditions.
• Reflux of contrast into the azygos vein: Can also be seen with massive pulmonary emboli, cor pulmonale, right-sided heart failure, pulmonary arterial hypertension, obstruction of the main pulmonary artery, bilateral pneumothoraces, and positive pressure ventilation.
• Reflux of contrast into the inferior vena cava: Can also be seen with tricuspid regurgitation, hypovolemic or cardiogenic shock, and pulmonary embolism.
• Deformity and compression of intrapericardial structures: For example the cardiac chambers (flattened heart sign, shown above), coronary sinus, pulmonary trunk, intrathoracic segment of the inferior vena cava (covered by pericardium anteriorly).
• Angulation or bowing of the interventricular septum: Correlates with paradoxical motion of the septum. Can also be seen with pressure and/or volume overload of the right ventricle (constrictive pericardial disease, massive pulmonary embolism).

The image above is a CT pulmonary arteriogram from a young patient with a malignant pericardial effusion. We see the flattened heart sign (black arrow). However, the diameters of the superior and inferior venae cavae were normal, no reflux of contrast into the inferior vena cava or the azygos vein was seen, and no periportal edema was present. Echocardiography showed cardiac tamponade.

References

Restrepo CS, Lemos DF, Lemos JA, Velasquez E, Diethelm L, Ovella TA, Martinez S, Carrillo J, Moncada R, Klein JS. Imaging findings in cardiac tamponade with emphasis on CT. Radiographics. 2007 Nov-Dec;27(6):1595-610.