Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Mild enlargement of the cardiac silhouette is noted . The mediastinal and hilar contours are unremarkable . There is no pulmonary vascular engorgement . Hazy opacification within the left lung base with loss of the left hemidiaphragmatic contour on the frontal view may reflect atelectasis or infection . No large pleural effusion or pneumothorax is noted , though there is likely a small amount of pleural thickening within the left costophrenic angle . No acute osseous abnormalities are present .
    OUTPUT:
    
Patchy left basilar opacity could reflect atelectasis or infection .