三维梯度回波Dixon水脂分离序列在产前一周预测胎儿体重中的价值

The Value of Three-Dimensional Gradient-Echo Dixon Water-Fat Separation Sequence:Estimation of Fetal Weight Within one Week Before Labour

目的探讨三维梯度回波Dixon水脂分离序列在产前1周预测胎儿体重的价值。方法随机搜集2020年3月至8月本院行MRI检查后1周内分娩的胎儿数据。所有胎儿分娩前1周内均行三维梯度回波Dixon水脂分离序列扫描,把原始图像数据导入星云IX工作站,选择同相位图像进行胎儿分割及三维重组并计算体积,采用Baker方程预测胎儿出生体重,计算预测值与出生体重的误差。结果共纳入23例胎儿数据分析,MRI预测胎儿体重与出生体重的相关性显著(r=0.987,P<0.05);MRI预测胎儿体重与出生体重的平均相对误差为3.98%,相对误差小于5%、10%的比例分别为78%、96%,绝对误差小于100 g、250 g的比例分别为43%、91%;MRI预测体重与出生体重具有较好的一致性,Bland-Altman图示96%的点在95%一致性界限内。结论运用单次屏气三维梯度回波Dixon水脂分离技术预测胎儿体重是可行的,而且扫描时间短,孕妇一次屏气即可完成扫描,能快速、有效地预测胎儿体重。

Objective The advantage sofrapid three-dimensional volumetric imaging of magnetic resonance is that it spends less time in imaging and canparticipate in three-dimensional reconstruction in three directions simultaneously.The purpose of this study is to investigate the value of MR imaging with three-dimensional gradient-echo Dixon water-fat separation sequence(3 DmDIXONXDFFE)in evaluating fetal weight within one week before labour.Methods The data of fetuses were randomly collected,which delivered within one week after MRI examination in our hospital from March 2020 to August 2020.All fetuses were imaged with the Dixon method for water fat separation using 3 D gradient-echo techniques.The in-phase image of original image data was imported into IntelliSpace Portal Workstation for fetal segmentation and three dimensional reconstruction to calculate the volume automatically.After estimating the fetal weight by the Baker equation,the error between the predicted value and the actual birth weight was calculated.Results A total of 23 fetuses data were included in the analysis.There was significant correlation between the MRI-determined estimation of fetal weight and fetal birth weight(r=0.987,P<0.005).The average relative error of the estimation was 3.98%,of which the proportion of relative error below 5%and 10%was 78%and 96%,the proportion of absolute error below 100 g and 250 g was 43%and91%,respectively.According to the Bland-Altman scatter plots,96%of the points were within the 95%consistency limit,which indicated a good agreement between fetal birth weight and MRI estimation of fetal weight.Conclusion It is feasible to evaluate fetal weight by using the single breath holding three dimensional gradient echo Dixon water-fat separation technique.With one breath holding,pregnant woman can spend less time completing the scan,which is able to evaluate fetal weight quickly and effectively.