The role of cardiac magnetic resonance imaging in the evaluation of congenital pericardial defects.

Pericardial defects are rare congenital anomalies that result from failure of the pericardium to form properly during embryogenesis. In this article, we present a case of a patient with persistent atrial fibrillation who underwent a multimodality imaging evaluation that included cardiac magnetic resonance imaging. Our patient demonstrated secondary signs of a partial defect that was not directly visualized on imaging and was ultimately diagnosed during open surgical intervention. This case illustrates that a high level of suspicion should be maintained for patients who demonstrate secondary imaging findings that suggest the presence of an underlying pericardial defect. Magnetic resonance imaging is the preferred modality for evaluating the pericardium, because of its ability to image the heart in any plane, improved soft tissue contrast compared with computed tomography, and lack of radiation exposure to the patient. However, direct visualization may be limited by patient-specific factors, such as paucity of pericardial fat and the size and location of the defect. In such cases, surgical evaluation may be necessary.