Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral views of the chest were obtained . The heart is of normal size with unremarkable cardiomediastinal contours . There is an opacity in the left lung base adjacent to an elevated left hemidiaphragm , which is compatible with atelectasis , although pneumonia can not be excluded in the appropriate clinical setting . No diffuse pulmonary abnormality is seen . No pleural effusion or pneumothorax is present . No radiopaque foreign bodies are present . The osseous structures are unremarkable .
    OUTPUT:
    
Linear opacity adjacent to elevated left hemidiaphragm , compatible with atelectasis associated with an elevated left hemidiaphragm , but pneumonia is not excluded .