Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral views of chest demonstrate normal cardiomediastinal silhouette . There is mild unfolding of the thoracic aorta . The lung volumes are slightly decreased but stable . There is no pneumothorax , vascular congestion , or pleural effusion . There is a small opacity obscuring the left posterior costophrenic angle , which is likely due to a Bochdalek hernia . Apparent thickening along the left lateral basal pleural space is consistent with extrapleural fat as correlated with CT .
    OUTPUT:
    
Bochdalek hernia likely accounts for a small opacity in the left posterior lung base . However , as this appears slightly more prominent than on prior studies , suggest a repeat CXR to exclude an adjacent pneumonia if symptoms persist .