Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is atelectasis at the left lung base and left perihilar region . Additionally , blunting of the left costophrenic angle suggests possible small pleural effusion . Right lung is essentially clear . There is no evidence of pneumonia , pulmonary edema or pneumothorax . Mild cardiomegaly is persistent .
    OUTPUT:
    
1 . Possible small left pleural effusion . 2 . No evidence of pneumonia .