Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Inspiratory volumes are slightly low . There is moderate cardiomegaly . The aorta is calcified and mildly unfolded . There is upper zone redistribution , without overt CHF . There is patchy opacity in the retrocardiac region , with partial obscuration of the left hemidiaphragm . The possibility of slight elevation of left hemidiaphragm can not be excluded . Minimal atelectasis at the right base . Trace blunting of the right costophrenic angle . No gross left effusion .
    OUTPUT:
    
1 . Patchy opacity at the left base could reflect atelectasis , but the possibility of an infectious infiltrate and left lower lobe can not be excluded . 2 . Mild upper zone redistribution , without overt CHF . 3 . Cardiomegaly , in keeping with findings on the ___ chest CTA .