Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral chest radiographs demonstrate cardiomediastinal contours are unchanged . Appearance of a left lower lung opacification on the frontal view appears to correspond with a prominent pericardial fat pad , better assessed on the lateral view and stable across multiple prior chest radiographs . Overall , lungs appear clear . No pleural effusion or pneumothorax is identified . Aortic knob calcifications again identified .
    OUTPUT:
    
No acute intrathoracic process . No overt pulmonary edema .