Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Left basilar opacity is likely due to atelectasis in setting of low lung volumes . Elsewhere , the lungs are clear . There is no consolidation worrisome for pneumonia , effusion , or edema . The cardiomediastinal silhouette is within normal limits . On the lateral view , catheter is partially seen projecting over the retroperitoneal region .
    OUTPUT:
    
Low lung volumes without definite acute cardiopulmonary process .