Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is increased retrocardiac opacity with air bronchograms new from ___ , with additional subsegmental linear atelectasis at the left base . The cardiac silhouette remains top normal , the mediastinal contours are normal . There is no pneumothorax or significant effusion .
    OUTPUT:
    
New retrocardiac opacity which is concerning for pneumonia , and could be better evaluated with dedicated upright and lateral chest radiographs .