Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A right - sided Port - A - Cath is noted with the tip terminating at the cavoatrial junction . There are slightly asymmetric lung volumes , left greater than right , but there is no pneumothorax or pleural effusion . There is linear opacity in the right apex which is poorly characterized due to overlying external structures and portable technique . There is no pulmonary edema . The cardiomediastinal silhouette is within normal limits . Of note , there is a necklace overlying the upper mediastinum , but without significant obscuration of the underlying structures .
    OUTPUT:
    
Linear opacity in the right upper lung is likely due to fcal parenchymal scarring or atelectasis . Recommend PA and lateral chest radiograph to better characterize this finding and to exclude scar carcinoma .