Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A subtle medial right basilar opacity is seen which may be due to atelectasis , although an infectious process is not excluded . Left lung is clear . There is no pleural effusion or pneumothorax . Cardiac and mediastinal silhouettes are unremarkable .
    OUTPUT:
    
Subtle medial right basilar opacity may be due to atelectasis and overlap of vascular structures , although an early infectious process is not excluded in the appropriate clinical setting , however , felt less likely .