Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There are low lung volumes . Left basilar atelectasis is seen . Trace left pleural effusion is difficult to exclude . No pneumothorax is seen . The cardiac and mediastinal silhouettes are unremarkable . There is no evidence of free air beneath the diaphragms . Residual barium is seen in the partially imaged colon .
    OUTPUT:
    
Left basilar atelectasis ; difficult to exclude small left pleural effusion . No evidence of free air beneath the diaphragms . Evidence of dense contrast in the partially imaged colon .