Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: In comparison to the prior supine radiograph performed several hours earlier , lung volumes have improved slightly . There has also been interval normalization of the appearance of the cardiomediastinal silhouette . No other interval change .
    OUTPUT:
    
Interval normalization of the cardiomediastinal silhouette since the supine radiograph performed several hours earlier , suggesting that the apparent widening seen on the prior study was likely due to positioning and technique .