Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable AP upright chest radiograph obtained . A subtle vague opacity in the left lower lung is seen adjacent to the left heart border which could represent tiny focus of pneumonia , though due to low lung volumes , evaluation is somewhat limited . Otherwise , the lungs are clear . No signs of pulmonary edema or effusion . No pneumothorax . Heart and mediastinal contours are normal . Bony structures are intact .
    OUTPUT:
    
Subtle opacity at the left lung base adjacent to the left heart border , question early pneumonia . Consider repeat radiographs with dedicated PA and lateral views with more optimized inspiratory effort to better assess .