Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size is normal . The aorta is mildly tortuous and demonstrates mild atherosclerotic calcifications . Pulmonary vasculature is normal . Patchy opacity within the left lung base with blunting of the left costophrenic angle appears chronic , and may reflect scarring with small left pleural effusion or pleural thickening . There is streaky atelectasis in the right lung base . No focal consolidation , right pleural effusion or pneumothorax is demonstrated . Clips from prior cholecystectomy are seen in the right upper quadrant of the abdomen . There are no acute osseous abnormalities . Mild degenerative changes are noted in the thoracic spine .
    OUTPUT:
    
No substantial interval change from the previous radiograph . Chronic left basilar scarring and blunting of the left costophrenic sulcus , possibly suggestive of a small left pleural effusion or pleural thickening . No focal consolidation .