Imaging of the pericardium requires understanding of anatomy and the normal and abnormal physiology of the pericardium. MR imaging is well-suited for answering clinical questions regarding suspected pericardial disease. Pericardial diseases that may be effectively imaged with MR imaging include pericarditis, pericardial effusion, cardiac-pericardial tamponade, constrictive pericarditis, pericardial cysts, absence of the pericardium, and pericardial masses. Although benign and malignant primary tumors of the pericardium may be occasionally encountered, the most common etiology of a pericardial mass is metastatic disease.