优选序列MRI测量胎儿股骨长度

目的 评价MRI测量胎儿股骨长度（FL）的价值，并选择最优序列。方法 回顾性分析205胎胎儿股骨MRI，包括弥散加权成像（DWI）、单次激发快速自旋回波（SSFSE）、快速稳态梯度回波（FIESTA）及快速反转恢复运动抑制（FIRM）序列图像及超声资料，对各序列图像质量进行评分，比较所测FL与超声测值的差异。结果 各序列MRI显示胎儿股骨干及骨骺端图像质量评分差异具有统计学意义（P<0.05）；DWI图像质量评分明显高于SSFSE、FIESTA及FIRM序列图像（P均<0.05），FIESTA序列图像质量评分高于SSFSE及FIRM序列图像（P均<0.05），SSFSE序列图像质量评分高于FIRM序列图像（P<0.05）。采用DWI测量的205胎FL结果与超声测值差异无统计学意义（P>0.05），而以SSFSE、FIESTA及FIRM序列图像所测FL与超声测值比较差异均有统计学意义（P均<0.05）。结论 MR可为临床提供能够直接显示胎儿股骨长轴的图像；DWI用于测量胎儿FL较其他MR序列更为精准。

Optimal sequence MRI for measurement of fetal femur length

Objective To observe the value of MRI in measuring fetal femoral length (FL), and to select the optimal sequence. Methods Data of MRI including diffusion weighted imaging (DWI), single shot fast spin echo (SSFSE), fast imaging employing steady-state acquisition (FIESTA) and fast inversion recovery motion insensitive (FIRM) sequence imaging, as well as ultrasound of 205 fetal femurs were retrospectively analyzed. The image quality of MR sequences were scored, and FL values measured with MR sequences and ultrasound were compared. Results There were significant differences of image quality scores of fetal femoral shaft and epiphysis between each two MR sequences (all P<0.05). The imaging quality score of DWI was significantly higher than that of SSFSE, FIESTA and FIRM sequence (all P<0.05), while of FIESTA sequence was higher than of SSFSE and FIRM sequence (both P<0.05), of SSFSE sequence was higher than of FIRM sequence (all P<0.05). There was no significant difference of FL values of 205 fetuses measured with DWI and ultrasound (P>0.05), but significant differences of FL values were found among SSFSE, FIESTA and FIRM sequences and ultrasound (all P<0.05). Conclusion MRI could provide direct images of fetal femur long axis for clinic. DWI could be used to measure fetal FL more accurately than other MR sequences.