Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP upright portable chest radiograph is obtained . There is a poorly defined opacity at the left lung base , which could reflect crowding of bronchovasculature and underpenetrated technique , though the possibility of an early pneumonia can not be excluded . Consider dedicated PA and lateral view to better assess . No large effusions or pneumothorax is seen . The heart size appears grossly stable . No mediastinal contour abnormalities are seen . Bony structures are intact .
    OUTPUT:
    
Subtle opacity at the left lung base could represent crowding of bronchovasculature though in the correct clinical setting , a pneumonia can not be excluded . If needed , a dedicated PA and lateral view may be obtained to further assess .