中文摘要：

目的研究对比剂剂量及注射速率相同的情况下,患者个体因素如性别、年龄、身体质量指数（BMI）等对上腹部增强CT门静脉期肝实质强化效果的影响。方法本研究共纳入87例患者,通过身高及体重的测量值计算患者的BMI数值。对所有患者均采用同一扫描方案进行常规上腹部三期动态增强CT扫描。对比剂剂量为93ml,注射速率为4ml/s。通过PACS系统测量各患者门静脉期肝实质增强CT值及门脉-肝实质对比度。比较不同分组间门静脉期肝实质增强CT值及门脉-肝实质对比度差异。结果男女性门脉期肝实质增强CT值均值分别为（45.56±13.77）HU（〈50HU占61%）和（55.15±13.93）HU,女性较男性门脉期门脉-肝实质对比度高29%。BMI〈18.5、〉18.5〈24.0和BMI〉24.0这三组的门脉期肝实质增强CT值分别为（59.27±14.39）HU、（49.18±14.05）HU和（41.58±10.85）HU,其中〈50HU分别为17%、51%和77%;BMI〉24的门脉-肝实质对比度较其他两组分别低39%和13%。结论在固定的对比剂剂量和注射速率的情况下,性别及BMI对肝脏门脉期肝实质增强上影响较大;提示在临床应用中,对比剂剂量的选择应考虑性别及BMI对门脉期强化程度的影响,男性及BMI较高（〉24）的患者应使用更大的剂量。

英文摘要：

Objective To investigate the effects of liver enhancement in portal phase of abdominal CT on age,gender and body mass index（BMI）at the same volume and injection rate of contrast media.Methods 87patients（59males and 28 females,52.0±12.1years old）were enrolled in this study.The BMI of each patient was recorded.All patients underwent the routine dynamic enhanced abdominal CT with the same protocol.The volume and injection rate of contrast agent for every patient was 93 ml and 4ml/s,respectively.TheΔHU of the liver parenchyma and the portal-to-liver rate in the portal phase were chose as the quantitative index and measured via the PACS.The differences of index with gender,age and BMI were compared respectively.Results The HU of the liver parenchy main portal phase of male and female patients was 45.56±13.77（61%less than 50HU）and（55.15±13.93）HU（36%less than 50HU）,respectively.The portal-to-liver rate of female patients was 29% higher than that of male patients.The HU of the liver parenchyma in portal phase with different BMI（18.5,18.5~24and 24）was（59.27±14.39（17%less than 50HU）,49.18±14.05（51%less than 50HU）and 41.58±10.8HU（77%less than 50HU）,respectively.The portal-to-liver rate in the portal phase of the patients whose BMI24was 39%and 13%lower than that of patients whose BMI18.5and whose18.5BMI24,respectively.Conclusion With the same volume and injection rate of contrast media,the differences of gender and BMI would impact the liver enhancement in portal phase of abdominal CT,which indicates that the contrast media volume should be determined by the gender and BMI.From our result,the male patients or the patients whose BMI lager than 24 need more volume of contrast media for the abdominal CT.