摘要目的:比较二氧化碳（CO 2）、空气用于CT 仿真结肠镜（CTVC）检查的效果及肠道清洁度对息肉性病变检出率的影响。 方法:选取杭州师范大学附属医院2015年10月至2020年11月行CTVC检查患者186例，采用随机数字表法分为CO 2组和对照组，每组93例。CO 2组经肛门注入CO 2充盈肠腔，对照组经肛门注入空气充盈肠腔。比较两组Boston肠道准备量表（BBPS）评分及腹胀评分、视觉模拟量表（VAS）评分、舒适程度（BCS）评分，观察两组息肉检出率。 结果:按BBPS评分，CO 2组、对照组肠道清洁度好（≥7分）分别为62例、60例，肠道清洁度差（<7分）分别为31例、33例。检查中，两组腹胀评分、VAS评分、BCS评分差异均无统计学意义（均 P>0.05）；检查后30 min，CO 2组腹胀评分、VAS评分分别为（2.21±0.40）分、（1.43±0.34）分，均明显低于对照组的（3.50±0.49）分、（3.03±0.55）分（ t=2.59、2.38，均 P<0.05）；检查后60 min，CO 2组腹胀评分、VAS评分、BCS评分分别为（1.15±0.39）分、（1.22±0.28）分、（1.27±0.35）分，均低于对照组的（2.16±0.43）分、（1.91±0.32）分、（1.85±0.37）分（ t=2.45、2.27、2.40，均 P<0.05）。CO 2组小息肉（<6 mm）检出率为32.7%（34/104），大息肉（≥6 mm）检出率为88.1%（37/42）；对照组小息肉检出率为29.0%（29/100），大息肉检出率为85.1%（40/47）；两组大、小息肉检出率差异均无统计学意义（均 P>0.05）。CO 2组、对照组肠道清洁度好者大息肉检出率分别为92.3%（24/26）、89.7%（26/29），均明显高于肠道清洁度差者［81.3%（13/16）、77.8%（14/18）］（χ 2=6.03、6.44，均 P<0.05）；CO 2组、对照组肠道清洁度好者小息肉检出率分别为41.9%（26/62）、42.9%（21/49）），明显高于肠道清洁度差者［（19.0%（8/42）、15.7%（8/51）］（χ 2=15.32、13.78，均 P<0.01）。 结论:采用CO 2充气的CTVC检查中患者舒适度更高，且对息肉性病变的检出率无影响；肠道准备的清洁度对CTVC检查的息肉检出率有显著的影响。

abstractsObjective:To investigate the efficacy of CT virtual colonoscopy with carbon dioxide (CO 2) versus room air and the effects of bowel cleanliness on polyp detection rate. Methods:A total of 186 patients who underwent CT virtual colonoscopy in the Affiliated Hospital of Hangzhou Normal University (Hangzhou Second People's Hospital), China between October 2015 and November 2020 were included in this study. They were randomly divided into CO 2 and control groups ( n = 93/group). In the CO 2 and control groups, CO 2 and room air were respectively injected through the anus to fill the intestinal cavity. The Boston Bowel Preparation Scale (BBPS) score, abdominal distension score, Visual Analogue Scale (VAS) score, Bruggrmann comfort scale (BCS) score and polyp detection rate were compared between the two groups. Results:According to BBPS score, there were 62 and 60 patients with good bowel cleanliness (BBPS score ≥ 7 points), and 31 and 33 patients with poor bowel cleanliness (BBPS score < 7 points) in the CO 2 and control groups, respectively. There were no significant differences in abdominal distension score, VAS score and BCS score measured during the examination between the two groups (all P > 0.05). At 30 minutes after examination, abdominal distension score and VAS score in the CO 2 group were (2.21 ± 0.40) points and (1.43 ± 0.34) points, respectively, which were significantly lower than those in the control group [(3.50 ± 0.49) points, (3.03 ± 0.55) points, t = 2.59, 2.38, both P < 0.05)]. At 60 minutes after examination, abdominal distension score, VAS score and BCS score in the CO 2 group were (1.15 ± 0.39) points, (1.22 ± 0.28) points, (1.27 ± 0.35) points, which were significantly lower than those in the control group [(2.16 ± 0.43) points, (1.91 ± 0.32) points, (1.85 ± 0.37) points, t = 2.45, 2.27, 2.40, all P < 0.05). The detection rate of small (< 6 mm) - and large (≥ 6 mm) -sized polyps in the CO 2 group was 32.7% (34/104) and 88.1% (37/42), respectively and they were 29.0% (29/100) and 85.1% (40/47) respectively in the control group. There were no significant differences in the detection rate of small- and large-sized polyps between CO 2 and control groups (both P > 0.05). The detection rate of large-sized polyps in patients with good bowel cleanliness in the CO 2 group was 92.3% (24/26) and 89.7% (26/29), respectively, which were significantly higher than those in patients with poor bowel cleanliness in the control group [81.3% (13/16), 77.8% (14/18), χ2 = 6.03, 6.44, both P < 0.05]. The detection rate of small-sized polyps in patients with poor bowel cleanliness in the CO 2 group was 41.9% (26/62) and 42.9% (21/49), respectively, which were significantly higher than those in patients with poor bowel cleanliness in the control group [19.0% (8/42), 15.7% (8/51), χ2 = 15.32, 13.78, both P < 0.01]. Conclusion:CT virtual colonoscopy with CO 2 injection is less uncomfortable than CT virtual colonoscopy with room air and it does not affect polyp detection rate. Bowel cleanliness has a remarkable effect on polyp detection rate in virtual colonoscopy.