Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart size is top normal . The aorta appears mildly tortuous , otherwise , the hilar and mediastinal contours are unremarkable . Dual - lead left - sided pacemaker is again seen , with leads terminating in the right atrium and right ventricle . Opacity at the left lateral lung base has slightly increased compared to the prior exam , likely secondary to atelectasis . There is no large pleural effusion or pneumothorax . Deformity of the distal right clavicle appears similar compared to the exam from ___ . Old healed lateral left eighth and ninth rib fractures are stable compared to the CT chest from ___ .
    OUTPUT:
    
Subtle increase in opacity at the left lateral lung base may be secondary to atelectasis ; however , an acute infectious process can not be excluded .