Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Single frontal view of the chest . The heart size is top normal , exaggerated by low lung volumes . The aortic knob is calcified . Pulmonary vascular markings are indistinct , compatible with mild pulmonary edema . No substantial pleural effusion or pneumothorax . Streaky linear retrocardiac left base opacity most likely represents atelectasis / scarring rather than consolidation .
    OUTPUT:
    
Mild pulmonary edema without substantial pleural effusion . Streaky linear retrocardiac left base opacity most likely represents atelectasis / scarring rather than consolidation .