Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is a new small area of opacity in the left lower lobe , obscuring the left heart border . While this could represent an area of volume loss , an infiltrate is also possible . The right hemidiaphragm continues to be mildly enlarged . The upper lungs are clear .
    OUTPUT:
    
Focal opacity in the left lower lobe could represent volume loss or infiltrate .