Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Left PICC is identified elbow tip is not clearly delineated . Persistent retrocardiac opacity is again seen as well as increased interstitial markings throughout the lungs . The cardiomediastinal silhouette is unchanged . Pulmonary nodules are better seen on prior CT scan . Expansile lytic lesion of the left lateral fourth rib there is again noted . Posterior fixation hardware seen in the visualized lumbar spine .
    OUTPUT:
    
Retrocardiac opacity potentially atelectasis although infection is also possible . Increased interstitial markings throughout the lungs could be from chronic interstitial process potentially with superimposed interstitial edema . Lytic expansile lesion of the left fourth again seen . Pulmonary nodules are better identified on prior CT scan .