儿童肝脏门静脉血流灌注对MR表观弥散系数的影响

Influence of portal blood flow in the liver of children on MR apparent diffusion coefficient

目的观察门静脉血流量变化对正常儿童肝脏表观弥散系数(ADC)值的影响。方法对15名健康儿童,在空腹及餐后60min时,用1.5T磁共振扫描仪重复进行肝脏扫描,对扫描后处理得到的肝右前叶及右后叶的ADC图进行ROI分析。对受试儿童在空腹状态及餐后的门静脉流量值及其在不同b值下空腹状态、餐后的肝脏各相应ROI平均ADC值,分别进行比较分析。结果餐后门静脉血流量显著增加,平均增加102.27%。b=750s/mm2时,空腹状态、餐后肝右叶的ADC值差异无统计学意义,而b=250s/mm2时差异有统计学意义;b=500s/mm2时,空腹状态、餐后肝右后叶的ADC值差异无统计学意义,而右前叶差异有统计学意义。结论选择较高b值有可能减轻血流灌注对儿童肝脏ADC值的影响。

[Objective To investigate the influence of portal blood flow in the liver of children on MR apparent diffusion coefficient （ADC）. Methods Fifteen healthy children underwent 1.5T MR at fasting state and 60 rain after standard diets. The regions of interest （ROD of ADC map was analyzed. The average value of ADC and portal blood flow of the liver were compared between fasting state and after feeding. Results Portal blood flow significantly increased after meal, and the mean increasing rate was 102.27%. No significent difference was found in ADC values of between fasting state and 60 min after standard diets when b= 750 s/mm^2 , whereas there was significant difference when b= 250 s/mm^2. When h= 500 s/mm^2 , there was significant difference in anterior right lobe, but no significant difference was detected in posterior right lobe. Conclusion A higher b value may minimize the influence of perfusion changes in diffusion-weighted MR study on liver in children.