Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size is borderline enlarged . The aorta remains tortuous and diffusely calcified . The hilar contours are stable . Crowding of the bronchovascular structures is likely attributable to low lung volumes . No overt pulmonary edema is seen . Streaky bibasilar airspace opacities are more pronounced on the left rather than right , and may be slightly improved compared to the prior study . No pleural effusion or pneumothorax is demonstrated , and there are no displaced fractures noted .
    OUTPUT:
    
Bibasilar airspace opacities most likely reflective of atelectasis though aspiration is not excluded . Overall , the aeration of the lung bases is slightly improved compared to the prior exam .