Pericardial agenesis (partial) is a rare cardiac defect. Radiologically, it presents with the following :

• levoposition of the heart
• prominent pulmonary artery
• air interface in the aorto-pulmonary window or between the base of the heart and the diapgragm

CT-scan is better than MRI for this diagnosis, since it has better spatial resolution. The pericardial defect will be seen. A complete pericardial defect is a benign condition, while patients with partial agenesis may have cardiac herniation through the defect. They should be managed surgically.