Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There appears to be a new left lower lobe focal opacity compared to the prior exam . This could be secondary to CHF exacerbation , or atelectasis , however an infiltrative process can not be ruled out . The bilateral pleural effusions appear to be stable . The heart size is stable compared to the prior exam . There again appears to be mild cardiac congestion with mild cephalization of the pulmonary vessels . The aorta appears to be tortuous .
    OUTPUT:
    
New left lower lobe focal opacification . This could be consistent with a CHF exacerbation or atelectasis , however an infectious process can not be ruled out .