Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes remain low , but somewhat improved compared to the previous study . Cardiac , mediastinal and hilar contours are unchanged . Pulmonary vasculature is not engorged . There is improved aeration of the lung bases with residual patchy opacities likely reflective of atelectasis . No focal consolidation , pleural effusion or pneumothorax is present . No acute osseous abnormality is seen .
    OUTPUT:
    
Persistently low lung volumes , but slight interval improvement in degree of aeration of the lungs . Patchy bibasilar airspace opacities likely reflective of atelectasis .