Constrictive Pericarditis: Understanding CT Imaging Characteristics

Constrictive pericarditis is a chronic condition characterized by thickening and scarring of the pericardium, which restricts normal heart function. Computed tomography (CT) plays a crucial role in diagnosing this condition by revealing both direct and indirect imaging features that help clinicians assess the severity and impact on cardiac performance.

Direct CT Findings in Constrictive Pericarditis

One of the most definitive signs observed on CT scans is abnormal thickening of the pericardium. In healthy individuals, the pericardial lining is thin and flexible, but in cases of constrictive pericarditis, it becomes rigid and often calcified. These calcifications appear as dense areas along the outer surface of the heart and are typically seen in multiple regions. The structural changes in the pericardium can significantly impair the heart's ability to expand during diastole, and CT imaging clearly captures these alterations.

Indirect CT Indicators of the Condition

While direct visualization of the pericardium is essential, CT scans also reveal secondary signs that support the diagnosis. A notable feature is the enlargement of both atria, while the ventricles remain relatively unaffected in size. This imbalance in chamber dimensions reflects the increased pressure within the heart due to restricted filling.

Additional Indirect Signs Observed on CT

Elevated venous pressure is another key indicator, often manifesting as dilation of the superior and inferior vena cava. This venous congestion can lead to hepatomegaly (enlarged liver) and the accumulation of fluid in multiple body cavities. Commonly, this includes pleural effusion (fluid around the lungs), and in some cases, ascites (fluid buildup in the abdominal cavity) may also be present. Advanced cases may even show peripheral edema in the lower extremities or along the chest wall due to chronic venous obstruction.

Pathophysiology Behind the Imaging Features

Constrictive pericarditis often develops as a result of long-standing inflammation, commonly from prior infections such as tuberculosis or other infectious or non-infectious causes. Over time, repeated episodes of inflammation lead to fibrosis and calcification of the pericardium. This structural damage impairs normal venous return to the heart, resulting in the various secondary findings seen on CT imaging.