• To review normal pericardial anatomy
• To review multimodality evaluation of pericardial disease
• To review a spectrum of pericardial diseases:
  • Congenital defect
  • Pericardial effusion
  • Pericarditis
  • Pericardial mass
• To review key imaging features in differential diagnosis

• Pericardial disease represents a heterogeneous group of congenital and acquired diseases that have variable clinical manifestations
• Diagnosis can be challenging and requires integration of clinical history, physical exam, and multimodality imaging findings
• Understanding of the pathophysiology of pericardial disease is essential in recognition of various morphologic features

• Pericardium is a 1-2 mm thick serous envelope with outer parietal layer and inner visceral layer
• Pericardial sac is a potential space with up to 50 mL of serous fluid
• Visceral pericardium adheres to the heart and great vessels and forms recesses and sinuses

• Pericardial recesses arise from pericardial cavity proper, transverse sinus, or oblique sinus
• Pericardial cavity proper gives rise to right pulmonic vein recess, left pulmonic vein recess, and postcaval recess
• Transverse sinus lies posterior to AA and MPA, gives rise to superior aortic recess, inferior aortic recess, right pulmonic recess, and left pulmonic recess
• Oblique sinus lies posterior to LA, gives rise to posterior pericardial recess

• Fluid density
• No enhancement
• Crescentic or lenticular shape
• Communication with other pericardial recesses

• Early regression of the common cardinal vein → Incomplete development of pleuropericardial membrane
• Right common cardinal vein typically persists as SVC → Blood supply to the right pericardium is usually preserved → Right pericardial defects are uncommon
• Partial absence is more common on the left (70%) than the right (17%), total absence is rare
• Associated congenital anomalies: ASD, PDA, Tetralogy of Fallot
• Complications:
  • Herniation of chambers → Torsion or ischemic necrosis
  • Epicardial coronary compression

• Abnormal bulge of left heart border
• Interdigitation of lung between aorta and MPA
• Interdigitation of lung between diaphragm and inferior cardiac surface

• Herniation of RA/RV through pericardial defect
• Extra bulge in right heart border
• Can simulate a mass on CXR

• Enlarged cardiac silhouette
  • Can be difficult to differentiate cardiomegaly from effusion
• Rapid change in cardiac silhouette size is suggestive of pericardial effusion
• “Water bottle” heart

• CT attenuation: < 10 HU, MR signal: Low T1, high T2
• Etiology: Pericarditis, congestive heart failure

• CT attenuation: 20 - 40 HU, MR signal: High T1, high T2
• Etiology: Infection, malignancy, hypothyroidism

• CT attenuation: > 20 HU, MR signal: High T1, high T2
• Etiology: Trauma, aortic rupture, MI, coagulopathy, malignancy

• Causes: Trauma, surgery, fistula
• DDX:
  • Pneumopericardium: Air confined to outlines of cardiac silhouette
  • Pneumomediastium: Streaky, linear air throughout mediastinum

• Diastolic collapse of RA and RV
• Right to left septal bowing with septal bounce
• IVC and hepatic veins distension
• Swinging of the heart within pericardium

• ↑ RV pressure → Right to left septal bowing %rarr; ↓ LV Filling
• ↓ Cardiac output → Reflux into dilated IVC and hepatic veins

• Inflammation of pericardium
• Etiology:
  • Infection, radiation, collagen vascular disease, uremia, myocardial infarction, cardiac surgery
• Imaging features:
  • Non-calcified pericardial thickening + enhancement
  • Pericardial effusion and edema
  • Inflammatory fat infiltration in mediastinum
  • Abnormal FDG uptake of pericardium

• Pericardial thickening > 4 mm
• Pericardial calcification
• (both suggestive but not diagnostic of constriction)
• Morphologic features
• Ventricular interdependence
• Pericardial-epicardial adherence

• Pericardial calcification reported in up to 30% of patients with constrictive pericarditis
• Can be focal or diffuse

• Thickened pericardium
• Tubular ventricles with dilated atria
• Dilated IVC and hepatic veins
• Signs of heart failure with large pleural effusions

• Ventricles unable to expand due to pericardial constriction
• During respiratory cycle, changes in RV filling affect LV filling

• Tagging sequence nulls signal in straight line or grid pattern
• Can be used to evaluate myocardial contraction and pericardial-myocardial adherence

• Margins/growth pattern
• Attenuation/signal
• Enhancement
• Lymphadenopathy
• Systemic findings

• Pericardial cyst
• Pericardial hematoma
• Pericardial lipomatous hypertrophy
• Benign tumors
• Malignant tumors

• Most common benign pericardial mass
• Pinch off of blind ending parietal pericardial recess during development
• Most common location: Right cardiophrenic angle (80%)
• Imaging findings:
  • Smoothly marginated cystic mass
  • No internal septations
  • No contrast enhancement
  • ± Peripheral calcification
• DDX: Thymic cyst, foregut duplication cyst, pericardial lymph node

• Etiology: Trauma, surgery, myocardial infarction, anticoagulation
• Imaging findings:
  • Variable attenuation/signal depending on age of blood products
  • No enhancement
  • ± Peripheral calcification in chronic hematoma
• DDX: Pericardial cyst, neoplasm
• Key to dx: Clinical history

• Unencapsulated proliferation of fat
• Can encase vessels and cause obstructive symptoms

• Most common benign pericardial tumor
• Encapsulated fat attenuation/signal mass

• Metastatic disease is by far the most common pericardial tumor:
  • Spread by direct invasion, hematogenous, and lymphatic spread
• Pericardial mesothelioma:
  • 50% of primary pericardial malignancy
  • Variable association with asbestos exposure
  • Irregular nodular thickening of the pericardium

• Irregular nodular thickening of the pericardium
• Infiltrative growth pattern
• Angiosarcomas typically arise from the right atrial wall near the AV groove
• Other sarcomas typically arise from the left heart

• Primary lymphoma isolated to the heart and pericardium is rare
• Usually secondary lymphoma in the setting of widespread disease
• Irregular nodular thickening of the pericardium
• Pericardium effusion
• Associated systemic lymphadenopathy

• Congenital absence of pericardium is more commonly seen on the left; look for heart contour abnormality or abnormal interdigitation of lung tissue to infer its absence
• Pericardial effusion can be transudative, exudative, or hemorrhagic depending on underlying etiology
• Development of pericardial tamponade depends on volume of fluid, rate of accumulation, and compliance of pericardium
• Pericardial tamponade compresses lower pressure right heart and impedes diastolic filling
• Pericarditis is associated with pericardial thickening, enhancement, and effusion
• Diagnosis of constrictive pericarditis depends on morphologic and dynamic features of impaired diastolic filling; pericardial thickening alone is not enough for the diagnosis
• Differential diagnosis of pericardial mass depends on attenuation, margins, growth pattern, enhancement, and associated systemic findings

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Acknowledgements

• Linda C. Chu
• Cheng Tin Lin
• Pamela T. Johnson
• Stefan L. Zimmerman
• Elliot K. Fishman