胎儿肝脏MRI信号强度的意义

Significance of MRI Signal Intensities in Fetal Liver

目的：探讨宫内胎儿肝脏的生长发育状况。材料和方法：采用超导0．35T磁共振成像仪，对44例中、晚孕程孕妇进行MR成像，观察、分析其中42例正常胎儿肝脏的形态结构、信号变化。结果：胎肝的形态、大小以及肝内的门静脉、肝静脉等被良好显示。在T1WI上，孕32周前，胎儿肝脏的信号呈不均匀的高信号；在孕32周后，胎儿肝脏的信号呈均匀的一致的中等信号。在PDWI及T2WI上，胎儿肝脏的信号在不同的孕周均呈等信号。结论：MRI对胎肝的生长发育状态的研究有重要价值，胎肝在T1WI上均匀一致和中等信号（约孕32周后）代表着胎肝的发育成熟；而PDWI及T2WI对揭示胎肝的发育成熟不敏感。

Deducing the physiological meanings of fetal liver signal intensities. Materials and methods: 44 pregnant women were imaged with MR at 0.35T. The structures and signals of 42 normal fetus were analyzed. Results: Many structures of fetal liver were well demonstrated by MR imaging such as configuration, size, portal veins, hepatic veins and so forth. Before 32 weeks of pregnancy, hyper-heterogeneous signal intensity of fetal liver was shown on T_1 WI. 32weeks, there was iso - signal intensity of fetal liver on T_1WI. There was also iso - signal about fetal liver on PDWI and T2WI during different gestational weeks.Conclusion: It was extremely valuable for MRI to study fetal liver growth and development. The homgeneous, iso-signal intensity of fetal liver indicated the mature growth and development of fetal liver on T_1WI(after 32 weeks of pregnancy). But it was unsensitive for MRI of PDWI and T2WI to judge the growth and developmental maturities of fetal liver.