Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Again seen is severe cardiomegaly , unchanged in appearance since previous examination . Persistent retrocardiac opacity is most consistent with atelectasis . The lungs are otherwise clear . Mild mediastinal widening is likely related to semi upright positioning and low lung volumes . The trachea is again noted to be deviated rightward with associated soft tissue likely due to an enlarged thyroid .
    OUTPUT:
    
1 . Retrocardiac atelectasis without definite pneumonia . 2 . Persistent severe cardiomegaly 3 . Mild mediastinal widening likely related to patient positioning and low lung volumes . 4 . Stable rightward tracheal deviation is likely due to enlarged thyroid .