Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral upright chest radiograph demonstrates severe scoliosis of the thoracic spine , convex to the left . As demonstrated on CT obtained on the same day , there is a large hiatal hernia accounting for retrocardiac opacity . No focal opacities identified concerning for pneumonia . When compared to prior chest radiograph obtained on a ___ , there is been little interval change with stable appearance of cardiomediastinal contour , allowing for differences in patient positioning .
    OUTPUT:
    
No convincing opacity concerning for pneumonia .