胎儿主要器官的正常解剖及MR表现

目的了解胎儿主要器官的正常解剖及MR表现。方法对47例胎儿行快速MR成像检查，使用序列为单次激发快速自旋回波序列，观察主要正常器官的解剖和MR表现，包括脑、肺、心脏、肝、脾、胃肠道、肾脏、膀胱、骨骼、脊柱和皮下脂肪，并按不同的胎龄分组观察。结果47例胎儿MR检查结果表明：孕20周时，胎儿各主要器官均已发育。20周左右，大脑皮层光滑，无脑回、脑沟，之后脑回、脑沟逐渐缓慢形成；肺、气管、支气管均呈高信号，心脏、大血管及肝脾呈低信号，胃肠道、肾孟肾盏、膀胱呈高信号，肾实质为等信号，骨骼、肌肉呈低信号；脊柱20周已形成，皮下脂肪20周可见，随胎龄增长逐渐增多。结论快速MR成像能清楚显示胎儿各主要器官的正常解剖和发育变化，胎儿主要器官的解剖和MR表现与新生儿有较大的差别。

Normal anatomy and MR findings of fetal main organs at MR imaging

Objective To investigate normal anatomy and MR findings of fetal main organs. Methods Forty-seven fetus underwented fast MR imaging, SSFSE sequence was used, the normal anatomy and MR findings of fetal main organs was observed in different gestational age. The organs included: brain, lungs, heart, liver, spleen, gastrointestinal tract, urinary collecting systems, bladder, bones, spine, and subcutaneous fat. Results Results of MR in 47 fetus showed that the main organs had developed by 20-week -old fetus, about 20 weeks gestation, cerebral cortical surface was smooth, no cortical gyri and sulci, then cortical gyri and sulci developed slowly. The lungs, trachea, bronchus, gastrointestinal tract, renal collecting system and bladder showed high signal intensity; the heart, great vessels, liver, spleen, bones and muscles appeared hypointense; the kidneys appeared isointense, the spine had developed and subcutaneous fat was seen in 20-week-old fetus, the subcutaneous fat increased with fetus maturating. Conclusion Normal anatomy and MR findings of fetal main organs were clearly showed by fast MR imaging, and they are different from the newborns.