Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The study is somewhat limited due to the apical lordotic view . There is a vague opacity in the right lung base which obscures the right hemidiaphragmatic contour . The lungs are otherwise clear . The hilar and cardiomediastinal contours are normal . There is no pleural effusion or pneumothorax . The pulmonary vascular markings appear normal . Incidental note is made of an old left clavicular fracture .
    OUTPUT:
    
Probable mild atelectasis at the right lung base , though pneumonia can not be excluded in the right clinical setting . A more optimized PA and lateral chest radiograph may be useful to further characterize this finding .