Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Single portable view of the chest was compared to CT scan from earlier the same day . Dense left basilar opacity is compatible with combination of left lower lobe collapse and parenchymal opacities in the left upper lobe . Left pneumothorax is demonstrated , both superiorly and at the lung base and along the mediastinum . Right lung is grossly clear . Cardiomediastinal silhouette is grossly unremarkable , although shifted to the left . Osseous and soft tissue structures are unremarkable .
    OUTPUT:
    
Left - sided pneumothorax as seen on prior CT scan . Dense left basilar opacity compatible with left lower lobe collapse and opacity in the left upper lobe as well .