Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac , mediastinal , and hilar contours are normal . The pulmonary vascularity is not engorged . A patchy opacity is noted in the left lung base . The right lung is grossly clear . No pleural effusion or pneumothorax is present . There are no acute osseous findings .
    OUTPUT:
    
Patchy opacity in the left lung base may reflect an area of infection .