Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Cardiac borders are partly obscured by a moderate sized left - sided pleural effusion with suspicion for substantial associated atelectasis involving the inferior part of the lingula and basilar segments of the left lower lobe . There is no net shift of midline structures . Aorta appears mildly tortuous . Right lung appears clear , without pleural effusion .
    OUTPUT:
    
Substantial left - sided pleural effusion .