Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A portable frontal chest radiograph demonstrate multiple support lines and tubes which appear unchanged in position , allowing for differences in patient positioning . There is slightly increased linear atelectasis in the right base , but retrocardiac opacity continues to improve . The small left pleural effusion is unchanged . There is no pneumothorax .
    OUTPUT:
    
Slightly increased right base linear atelectasis and continued mild improvement of retrocardiac opacity . Otherwise unchanged exam .