磁化率传递成像及弥散加权成像在中晚孕期正常胎儿胎盘及大脑中的应用价值

Evaluation of normal placenta and fetal brain during the second and third trimester by diffusion weighted imaging and magnetization transfer imaging

目的:探究磁化传递成像(MTI)和弥散加权成像(DWI)技术在中晚孕期正常胎儿胎盘及大脑中的应用价值。方法:对60例患者进行常规胎盘和胎儿脑部MTI及DWI的扫描,分别计算感兴趣区磁化传递率(MTR)和表观弥散系数(ADC)值,并对胎盘和胎儿脑部的MTR及ADC值进行比较。结果:正常胎盘MTR及ADC值均高于胎儿大脑MTR及ADC值(P=0.002及0.000)。中孕期胎盘ADC值明显高于胎儿大脑ADC值(P=0.000);晚孕期胎盘MTR及ADC值均明显高于胎儿大脑MTR及ADC值(P=0.003及0.000);晚孕期胎盘与胎儿大脑MTR值存在正相关(P=0.022,ρ=0.331)。结论:中晚孕期,由于胎儿大脑不断发育成熟,胎盘组织中结构大分子物质(如蛋白质、脂质、核酸等)的含量随之升高,以支持胎儿神经系统的发育。

Objective:To discuss the value of diffusion weighted imaging(DWI)and magnetization transfer imaging(MTI)in evaluating normal placenta and fetal brain during the second and third trimester.Methods:DWI and MTI were performed in60 patients.The magnetization transfer ratio(MTR)and apparent diffusion coefficient(ADC)values of the placenta and fetal brain were measured and compared.Results:The MTR and ADC values of the placenta were significantly higher than those in the fetal brain(P=0.002 and 0.000).In the second trimester,the placental ADC values were significantly higher than ADC values in the fetal brain(P=0.000).During the third trimester,the MTR and ADC values of the placenta were significantly higher than those in the fetal brain(P=0.003 and 0.000).Positive correlation was found in the MTR values between the placenta and the fetal brain(P=0.022,ρ=0.331).Conclusion:During the second and third trimester,with the mature of the fetal brain,macromolecules in the placenta(proteins,lipid,nucleic acid,et al)increase to support the normal development of fetal central nervous system.