Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Evaluation is limited due to underpenetration on technique and patient body habitus . Streaky opacification of the left lung base is again noted compatible with scarring or atelectasis . Prominence of interstitial markings may be related to underpenetration but underlying pulmonary edema or atypical infection is difficult to exclude . No significant pleural effusion or pneumothorax is detected . The cardiomediastinal silhouette remains enlarged but stable . Calcification at the aortic knob is noted . The trachea appears midline .
    OUTPUT:
    
1 . Limited examination with unchanged left basilar atelectasis or scarring . 2 . Prominence of interstitial lung markings likely relate to underpenetration although pulmonary edema or atypical infection is not excluded .