单次激发快速自旋回波序列MR检查在正常胎儿中的应用

Application of single-shot fast spin-echo sequence in MR imaging of normal fetus

目的观察单次激发快速自旋回波序列(SSFSE)在胎儿解剖结构方面的显示能力,探讨其在胎儿MR检查中的临床应用价值。方法对14胎20周以上正常胎儿行MR检查,采用SSFSE序列对胎儿头颅、躯干行轴位、冠状位、矢状位扫描,观察胎儿各系统主要器官,包括脑、肺、心脏、肝、脾、胃肠道等的解剖和MR表现。结果孕20周时,胎儿各主要器官均已发育。中枢神经系统:在SSFSE图像脑室系统高信号的衬托下,大脑三层结构清晰可辨,皮层及脑室旁生发层呈低信号,白质呈稍高信号。脑室系统呈生理性扩大状态,30周后脑沟、回形成逐渐明显;非神经系统:SSFSE图像肺、气管、支气管均呈高信号,胃泡、肾盂、肾盏、膀胱等空腔脏器呈高信号,肠管信号混杂,心脏、大血管、肝、脾及双侧肾脏呈等低信号。结论 SSFSE可清楚显示胎儿各主要器官的正常解剖和发育变化。

Objective To investigate the ability of single-shot fast spin-echo（SSFSE） sequence in delineating the anatomic structures of fetus,and to explore the clinical value of this sequence.Methods Fourteen normal fetuses with gestational age larger than 20 weeks underwent MR imaging 1 week within ultrasonic examination.SSFSE sequence was performed at the coronal,sagittal and axial view of the fetus body and the head.The normal fetus anatomy of brain,lungs,heart,liver,spleen,gastrointestinal tract,etc.and their MR manifestations were observed.Results The main organs of fetus had developed in 20 weeks gestation.In the central nervous system,against the high signal of the ventricular system,three layers of the cerebrum were identified,including the hypointense cortical gray matter,the hyperintense white matter,and the lower-signal-intensity germinal matrix.Cortical gyri and sulci developed significantly after 30 weeks gestation.The lungs,trachea,bronchi,stomach bubble,renal collecting system and bladder showed as high signal intensities,while gastrointestinal tract displayed mixed signal,the heart,great vessels,liver,spleen and kidneys appeared as hypointensities.Conclusion SSFSE sequence MR imaging can clearly show the normal anatomy of main fetal organs.