Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart is not enlarged . No CHF , focal infiltrate , effusion , or pneumothorax is detected . Within the limits of plain film radiography , no hilar mediastinal lymph nodes or pulmonary nodule is detected . Minimal linear atelectasis or scarring at the left lung base laterally is noted . There are mild degenerative changes of the thoracic spine .
    OUTPUT:
    
No acute pulmonary process identified . Minimal atelectasis or scarring at the left lung base .