Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is a vague opacity at the left lung base overlying the rib . The right lung is clear . The cardiomediastinal contour is normal . There is no pleural effusion or pneumothorax . Pleural surfaces are unremarkable . There is no pulmonary edema . Visualized osseous structures are normal .
    OUTPUT:
    
Vague opacity at the left lung base , not seen previously , given AP portable technique this could represent technique , though a very early pneumonia is difficult to exclude .