Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Dilatation of the aortic knob and descending thoracic aorta is compatible with known aortic aneurysm , better assessed on the prior CT . The heart size is normal . Hilar contours are normal . Linear atelectasis in the left lower lobe is present . No focal consolidation is identified . Blunting of the left costophrenic angle on the lateral view is compatible with a small pleural effusion , seen on the prior CT . No pneumothorax is identified . No acute osseous abnormality is seen . Clips are seen within the neck .
    OUTPUT:
    
Thoracic aortic aneurysm , better assessed on the prior reference CT , with small left pleural effusion . Left basilar subsegmental atelectasis .