Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is cardiomegaly , with unfolded aorta . There is patchy opacity at the left lung base with slight obscuration of the left hemidiaphragm , progressed slightly compared with earlier the same day ( 11 :53 a .m . ) . In the appropriate clinical setting , this could represent an early infiltrate . Right and left lungs are otherwise grossly clear . No right - sided effusion . There is mild upper zone redistribution , without overt CHF . Focal density questioned on the prior study was not specifically delineated . No focal nodule in this area is detected on the current examination .
    OUTPUT:
    
Possible early infiltrate , left base . Differential diagnosis could include some localized atelectasis .