Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Assessment is limited due to patient positioning . Mild to moderate cardiomegaly is re - demonstrated . Mediastinal and hilar contours are grossly unremarkable . No pulmonary edema is demonstrated . Patchy opacity in the retrocardiac region may reflect atelectasis . Infection is not excluded . A small left pleural effusion is likely present . The right lung is grossly clear . No pneumothorax is identified . No acute osseous abnormalities detected .
    OUTPUT:
    
Limited study due to patient positioning . Patchy retrocardiac opacity , potentially atelectasis but infection can not be excluded . Trace left pleural effusion may be present .