Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Opacity in the left lower lung is increased since ___ . There is no pulmonary edema , pleural effusion or pneumothorax . Aortic knob is calcified . Evaluation of heart size is difficult due to the low lung volumes ; however , it is most likely normal . There is no free air beneath the right hemidiaphragm . There is no acute osseous abnormality .
    OUTPUT:
    
Opacity in the left lower lung is increased since ___ and most likely represents pneumonia .