单层厚块单次激发快速自旋回波重T_2加权序列胎儿成像质量分析

Quality analysis of magnetic resonance fetography with a single-shot thick-slab turbo spin-echo sequence

目的评价单次激发厚层快速自旋回波(single-shot turbo spine cho,SSTSE)重T2加权序列行磁共振胎儿成像(magnetic resonance fetography,MRF)的图像质量及其影响因素。方法2006年4月至2008年2月间,因产前超声筛查诊断或怀疑胎儿异常的孕妇164例,在常规胎儿MRI检查基础上行MRF,采用横断、冠状、矢状多层面多角度对胎儿进行显示,并对MRF图像进行质量评价,分析图像质量与孕周、胎位和羊水的关系及图像质量降低的原因。结果所有胎儿的MRF检查均顺利完成。MRF能在一幅图像上同时捕捉胎儿的解剖和病理,半透明状态和整体表现相结合是对胎儿的一种全新显示。MRF成像质量与胎儿孕龄、胎位、羊水量无统计学差异(p>0.05)。运动伪影、卷褶伪影、母亲膀胱过度充盈可使图像质量降低。结论MRF提供了一种具有三维立体感的胎儿整体图像,且具有快速、多方位、可重复优质成像的特点,图像质量不受孕周、胎位和羊水的影响,可作为胎儿检查的一种辅助方法。

Objective To evaluate the quality and influencing factors of magnetic resonance fetography imaging with a single-shot thick-slab turbo spin-echo sequence. Methods From April 2006 to February 2008, 169 fetuses who were suspected as abnormal by means of ultrasound undertook MRF after conventional examinations. Fetuses could be shown from multi-slices and multi-angles by using traverse, coronal and sagittal images and MRF was evaluated as to the relationship of imaging quality with gestational age, fetal position and amount of amniotic fluid. Results MRF examination of all fetuses was performed smoothly. MRF with thick-slab method offered a global overview of fetal pathology or anatomy that might be captured in one image. The combination of overall appearance and translucency provided a new look at the fetus. There was no statistical difference among gestational age, fetal position and amount of amniotic fluid （P 〉 0.05）. Motion artifact, wrap artifact and maternal overfilling bladder could compromise the image quality. Conclusions MRF provides 3D fetal-overall image. MRF can be repeated to image at different orientations and different view angles quickly, its high quality image will not be influenced by gestational age, fetal position and amount of amniotic fluid. It may serve as an auxiliary method for fetal examination.