Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Linear opacities in the left lung base most likely represent atelectasis , however , underlying infection can not be excluded . There is no pleural effusion or pneumothorax . The cardiac and mediastinal contours are normal . Kyphosis of the thoracic and upper lumbar spine is noted .
    OUTPUT:
    
Linear opacity in the left lung base most likely represent atelectasis , however , infection can not be excluded .