3.0 T MR TrueFISP序列负间隔扫描经多平面重组显示胎儿股骨长轴的可行性研究

Feasibility Study of Multiplane Reformation to Show the Long Axis of Femur after Negative Interval Scanning with 3.0 T MR TrueFISP Sequence

目的探讨3.0 T MR真实稳态进动快速成像(TrueFISP)序列负间隔扫描后,应用多平面重组(MPR)技术显示胎儿股骨长轴的可行性。方法回顾性分析60例胎儿股骨的3.0 T MRI图像,产前超声提示胎儿股骨正常,孕周26~39周,均有对胎儿股骨进行负间隔TrueFISP序列扫描的图像。为获取胎儿股骨的标准长轴图像,由两位MR医师应用MPR技术分别对胎儿的股骨长轴进行修正重组。比较两位MR医师重组图像的质量,测量股骨长度并与超声测量结果进行比较。结果60例胎儿股骨TrueFISP图像中,27例(45%)直接获得了胎儿股骨的标准长轴图像,而33例(55%)没有获得标准图像。两位医师对这33例胎儿股骨行MPR,分别获得了90.9%(30/33)和87.9%(29/33)的成功率,其图像质量的评分分别为2.91±0.29和2.88±0.33,两者之间差异无统计学意义(Z=1.000,P=0.317)且具有高度一致性(ICC=0.845,P=0.000)。在TrueFISP图像上,两位医师测量股骨干长度分别为(60.42±5.86)cm和(60.35±5.87)cm,超声测量股骨干长度为(59.35±9.07)cm,三者之间差异无统计学意义(P>0.05)。结论3.0 T MR TrueFISP序列负间隔扫描后,应用MPR技术可以获取胎儿股骨的标准长轴图像,其测量结果与超声结果无差异。因此TrueFISP序列的负间隔扫描结合MPR技术可以弥补直接扫描不能获得胎儿股骨标准长轴图像的不足。

Objective To investigate the feasibility of using multiplane reformation(MPR)technique to display the long axis of fetal femur after 3.0 T MR true steady-state progressive imaging(TrueFISP)sequence negative interval scanning.Methods The 3.0 T MR images of fetal femur of 60 cases were retrospectively analyzed.The prenatal ultrasound indicated that the fetal femur was normal.The images of fetal femur were scanned by negative interval TrueFISP sequence from 26 to 39 weeks of gestation.To obtain a standard long axis image of the fetal femur,two MR physicians independently corrected and reconstructed the fetal long axis using the MPR technique.The quality and length of the fetal femur reconstructed by two MR physicians were compared,and the results were compared with those measured by ultrasound.Results Of the 60 fetal femoral TrueFISP sequence images,27(45%)obtained a standard long-axis femoral image directly,while 33(55%)did not obtain a standard image.Two physicians reconstructed the femur of the 33 fetuses with a success rate of 90.9%(30/33)and 87.9%(29/33),respectively.The image quality scores were(2.91±0.29)and(2.88±0.33),respectively.There was no statistical difference between the two(Z=1.000,P=0.317),and there was a high degree of consistency(ICC=0.845,P=0.000).In TrueFISP images,the length of femoral shaft measured by two physicians was(60.42±5.86)cm and(60.35±5.87)cm,respectively,and the length of femoral shaft measured by ultrasound was(59.35±9.07)cm,with no statistical difference among the three(P>0.05).Conclusion After negative interval scanning of 3.0 T MR TrueFISP sequence,After negative interval scan of T MR TrueFISP sequence,the standard long axis image of fetal femur can be obtained by MPR technique..Therefore,TrueFISP sequence negative interval scanning combined with MPR technology can make up for the lack of direct scanning which can not obtain the standard long axis image of fetal femur.