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Findings: Admission chest radiograph is remarkable for lack of definition of the left heart border. The heart shadow appears to be rotated to the left, but evaluation of the clavicles show no significant rotation. Images from an abdominal CT shows marked deviation of the heart into the left chest. There is no evidence of left lung volume loss. Note is made of absence of the pericardium.
Diagnosis: Congenital absence of the pericardium.
Discussion: This is a classic presentation of congenital absence of the pericardium. The chest radiograph shows displacement of the heart into the left chest, in the so called "LAO appearance" of the heart. The CT scan confirms the marked rotation laterally and posteriorly into the left hemithorax in this entity, APA and supine lateral radiograph is often diagnostic as the heart shadow is seen displaced into the posterior chest on the supine film.
Congenital absence of the pericardium is usually left sided, and felt to be related to premature obliteration of the duct of Cuvier. This causes incomplete formation of the parietal pericardium. In addition to the leftward deviation of the heart, lung can be seen interposed between the aorta and pulmonary artery, as well as between the left hemidiaphragm and cardiac silhouette. Partial defects are more common, and are associated with congenital heart disease in 30%. These partial defects can be life threatening, as transient herniation of the left atrium can occur.
References:
White, CS. MR Evaluation of the Pericardium and Cardiac Malignancies.
MRI Clinics of North America: 237-251.
Altman CA, Ettedgui JA, Wozney P, et al: Noninvasive Diagnostic Features of
Partial Absence of the Pericardium. Am J Cardiol 63:1536-1537, 1989.
Higgins CB, Caputo GR: Role of MR Imaging in Acquired and Congenital Cardiovascular
Disease. Am J Roentgenology 161:13-22, 1993.
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