Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Study is again somewhat limited however , better than examination from approximately 1 hr prior . There has been no relevant change compared to that study with re - demonstration of a retrocardiac opacity with possible subtle posterior correlate on lateral view .
    OUTPUT:
    
No relevant change compared to study from 1 are prior . This study is technically superior to the prior and re- demonstrates a retrocardiac opacity , probably atelectasis though a subtle underlying pneumonia can not be excluded in the appropriate clinical context .