Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Left pericardial opacity has slightly decreased measuring 11 mm . The lungs are otherwise clear . The mediastinal and cardiac contours are normal . There is no pneumothorax or pleural effusion .
    OUTPUT:
    
Left pericardial opacity has improved , but has not completely resolved . Another followup chest x-ray is suggested in a month .