Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP upright of the chest provided . Hemidiaphragm is elevated with left basal opacity , likely atelectasis vs . pneumonia . There is normal aeration of the right lung without definite signs of effusion . There is a left apical cap , which could represent fluid along the left lung apex . Heart size can not be assessed . Mediastinum is difficult to assess due to leftward patient rotation . Bony structures are intact .
    OUTPUT:
    
Findings as above with possibility of left lung base pneumonia not excluded . Please correlate clinically .