Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Both lungs are well expanded and clear . Faint opacity seen in the left lower lung in the retrocardiac region and also in the lateral view corresponds to crowded pulmonary vascular markings , which is also reflected on the prior radiograph from ___ . No opacities concerning for pneumonia . There is no pleural effusion . Heart size is top normal . Mediastinal and hilar contours are within normal limits .
    OUTPUT:
    
No acute cardiopulmonary process .