Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Single portable view of the chest is compared to previous exam from outside hospital performed the same day and chest x-ray from ___ . There is a retrocardiac opacity which appears somewhat more conspicuous thanon exam from earlier the same day . There is also blunting of the left lateral costophrenic angle . Diffuse increased interstitial markings are seen throughout , particularly at the right lung base . Cardiomediastinal silhouette is grossly unchanged as are the osseous and soft tissue structures .
    OUTPUT:
    
Retrocardiac opacity , potentially due to atelectasis given interval progression since earlier the same day however component of infection or effusion is also possible . Increased interstitial markings throughout the lungs most notably at the right lung base potentially due to low lung volumes however component of fluid overload is also possible .