Question: what does barium do in a ct scan
[{'answer': 'improve visualization', 'provenance': [{'wikipedia_id': '8834835', 'title': 'Barium sulfate suspension', 'start_paragraph_id': 1, 'start_character': 122, 'end_paragraph_id': 1, 'end_character': 143, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '8834835', 'title': 'Barium sulfate suspension', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 283, 'bleu_score': 0.8318346593229521, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5858082301902827297}, 'section': 'Section::::Abstract.'}]}]