Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac , mediastinal and hilar contours appear unchanged including moderate unfolding of the thoracic aorta . The heart is at the upper limits of normal size . There is no definite pleural effusion or pneumothorax . Air bronchograms can be seen in the medial retrocardiac region which may indicate a subtle left lower lobe opacity . The right humerus shows apparent inferior positioning compared to the glenoid consistent with chronic dislocation not significantly changed since earlier studies .
    OUTPUT:
    
Medial left basilar opacity suggested by vague opacity with air bronchograms , but not well evaluated . Atelectasis but potentially pneumonia could be considered , although this finding is not a definite source for infection .