Diagnostic imaging methods
A comprehensive approach is used to diagnose pericardial diseases:
- Echocardiography (TTE): First-line method. Inexpensive, accessible, excellent for detecting effusion and signs of tamponade. However, the method has "blind spots" and poorly visualizes thrombi, leaflet thickening, and loculated fluid.
- Computed tomography (CT): Performed with ECG gating. This is the best method for detecting calcifications (a sign of constriction). Delayed contrast-enhanced scans demonstrate inflammatory enhancement of the pericardium.
- Cardiac MRI: The gold standard for assessing loculated effusion, mass lesions, and the impact of pathology on cardiac function. Cine-MRI allows dynamic visualization of hemodynamic disorders.
- Chest X-ray (CXR): Informational value is limited. May show calcification or alteration of the cardiac silhouette (water-bottle heart) in massive effusion.
Congenital anomalies and cysts
Developmental anomalies include absence of the pericardium, resulting from impaired blood supply during embryogenesis.
- Congenital absence of the left pericardium: Most common. Scans show leftward displacement of the heart and interposition of lung tissue between the aorta and pulmonary artery. A partial defect is dangerous due to cardiac chamber strangulation (e.g., the left atrial appendage).
- Pericardial cysts: Benign fluid-filled lesions, often located in the right cardiophrenic angle. On MRI, they demonstrate high signal intensity on T2-weighted images and do not enhance with contrast.
Pericardial effusion and tamponade
The accumulation of pathological fluid (effusio pericardii) can be a transudate, exudate, or blood (haemopericardium). It occurs in infections, trauma, tumors, or renal failure. On lateral chest radiographs, the "sandwich" sign or epicardial fat pad sign can sometimes be observed.
Cardiac tamponade is a life-threatening condition in which fluid physically compresses the myocardium. The rate of fluid accumulation is more critical than its absolute volume. Compression severely restricts diastolic filling, leading to a drop in stroke volume and decreased cardiac output.
Pericarditis: from acute to constrictive
Acute pericarditis is most often viral in origin (e.g., Coxsackie B viruses) or occurs following a myocardial infarction. CT and MRI reveal effusion and intense contrast enhancement of the thickened, inflamed pericardial leaflets.
Constrictive pericarditis is the result of chronic scarring and calcification. Most commonly develops after radiation therapy or cardiac surgery.
- The pericardium thickens to more than 4 mm.
- Restriction occurs: the rigid shell prevents the chambers from expanding during diastole.
- Secondary CT signs include conical configuration of the right ventricle, dilation of the venae cavae and hepatic veins, and hepatomegaly (sometimes progressing to cardiac cirrhosis).
Briefly: answers to topical questions
What imaging features are used to differentiate constrictive pericarditis from restrictive cardiomyopathy?
To differentiate constrictive pericarditis from restrictive cardiomyopathy, pericardial thickness and calcification are assessed, as well as the motion of the interventricular septum.
| Sign | Constrictive pericarditis | Restrictive cardiomyopathy |
|---|---|---|
| Pericardial thickness (CT/MRI) | Pericardial thickening, typically at least 4 mm | Used for differential diagnosis with constrictive pericarditis |
| Pericardial calcification | May be detected; CT has high sensitivity for calcification | Pericardial calcification is not mentioned in the provided sources |
| IVS motion | Paradoxical motion depending on the respiratory phase (septal bounce), serpentine septal motion | No abnormalities in IVS motion are detected |
CT has the advantage in detecting pericardial calcification. MRI accuracy for the differential diagnosis of constrictive pericarditis and restrictive cardiomyopathy is 93%.
What are the most common primary benign and malignant pericardial tumors?
Among primary benign pericardial lesions, pericardial (mesothelial) cysts and lipomas are the most common. Sources indicate mesothelioma as a primary malignant pericardial tumor, but do not establish it as the most frequent among primary malignancies.
- Pericardial cysts are often asymptomatic; symptoms may occur due to compression of surrounding structures.
- Lipomas are characterized by low attenuation on CT and high signal intensity on T1- and T2-weighted MRI.
- Pericardial mesothelioma may present with pericardial effusion, sometimes with nodules or plaques on the pericardium.
What are the most common causes of hemopericardium?
Hemopericardium is most commonly associated with traumatic injuries to the heart and pericardium: lacerations, blunt chest trauma, and closed cardiac injuries.
Other causes include aortic dissection and rupture, rupture of ascending aortic arch aneurysms, myocardial ruptures, tumors, and metastases involving the pericardium.
Less commonly, hemopericardium may occur due to cardiac aneurysm rupture, myocardial abscesses, sepsis, and arrhythmogenic right ventricular dysplasia.
To easily differentiate the type of effusion on T1-weighted MRI, remember the signal intensity rule: simple transudate is dark (low signal), inflammatory exudate (with protein) is gray (intermediate signal), and blood changes in brightness depending on the stage of degradation.
Class and exam questions
Why is it important to differentiate constrictive pericarditis from restrictive cardiomyopathy?
Both conditions restrict diastolic filling of the heart and present with similar clinical features, but are treated differently. Pericarditis requires surgical pericardiectomy, while cardiomyopathy is treated medically or with transplantation.
How quickly does cardiac tamponade develop?
In rapid (acute) bleeding into the pericardial cavity, even 100–200 ml of fluid can cause clinically significant tamponade due to severe diastolic restriction.
Which tumors are most commonly found in the pericardium?
Secondary (metastatic) tumors occur 20–40 times more frequently than primary ones. These are usually metastases from lung cancer, breast cancer, or lymphoma.
What else to study on this topic
- Assessment of the septal bounce on MRI
- Differential diagnosis of pericardial sinuses and lymphadenopathy on CT
- The sandwich sign and radiographic signs of pericardial thickening
- Hemopericardium: the role of MRI in determining the age of hemorrhage
- Pathophysiology of venous congestion in constrictive pericarditis
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