Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Streaky opacity in the left base of hte left lung represents atelectasis ; otherwise , the lungs are clear without focal opacity , pleural effusion or pneumothorax . There is mild cardiomegaly . The mediastinal contours are normal .
    OUTPUT:
    
No acute intrathoracic process . Left basilar atelectasis and mild cardiomegaly .