Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes remain low . The heart size is unchanged , and within normal limits . The mediastinal and hilar contours are similar compared to the prior exam . There is crowding of the bronchovascular structures but no pulmonary edema is demonstrated . Linear opacities within the left lung base likely reflect subsegmental atelectasis . More patchy opacities in the lung bases also likely reflect atelectasis due to low lung volumes . No pleural effusion or pneumothorax is present . No acute osseous abnormalities demonstrated .
    OUTPUT:
    
Low lung volumes with patchy opacities at the lung bases likely reflective of atelectasis .