Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP upright and lateral views of the chest provided . Since the prior exam , there is improved aeration in the lower lungs . Lungs remain hyperinflated and lucent suggesting underlying emphysema . Heart size is suboptimally assessed but appears grossly stable . The mediastinal and hilar configuration is unchanged . There is no pneumothorax or large effusion . The bony structures are intact . No free air below the right hemidiaphragm .
    OUTPUT:
    
COPD without superimposed pneumonia . Improved aeration in the lower lungs compared with prior .