厚层负间距技术用于胎儿3T MR平衡式快速场回波序列扫描

Thick-layer negative-spacing technique applicated in fetal 3T MR balanced fast field echo sequence scanning

目的评估厚层负间距平衡式快速场回波(B-FFE)序列在胎儿3T MR检查中的应用价值。方法对91名孕妇采集胎儿头部常规层厚间距(层厚3 mm,层间距0 mm)及厚层负间距(层厚6 mm,层间距-3 mm)B-FFE序列图像,比较不同序列图像中胎儿侧脑室后角层面左侧额叶白质区(SNR额叶白质区)及左侧脑室后角(SNR侧脑室后角)的信噪比(SNR)、图像对比噪声比(CNR)、图像质量评分及特异吸收率(SAR),并记录采集时间。结果厚层负间距B-FFE序列图像的SNR额叶白质区、SNR侧脑室后角及CNR均高于常规层厚间距B-FFE序列图像(Z=-8.290、-8.290、-8.013,P均<0.001),其图像质量评分高于常规层厚间距B-FFE序列图像(χ^(2)=10.966,P=0.004),而SAR与常规层厚间距B-FFE序列图像差异无统计学意义(Z=-0.362,P=0.717)。厚层负间距B-FFE序列图像采集时间57 s,而常规层厚间距B-FFE序列为37 s。结论厚层负间距技术用于胎儿头部B-FFE序列扫描有助于提高图像质量,以清晰显示胎儿解剖结构及病变细节。

Objective To observe the application value of thick-layer negative-spacing balanced fast field echo(B-FFE)sequence in fetal 3T MR examination.Methods Fetal head B-FFE sequence images with conventional slice thickness and space(slice thickness 3 mm,slice space 0 mm)and thick slice negative space(slice thickness 6 mm,slice space-3 mm)were acquired in 91 pregnant women.The signal to noise ratio(SNR)of left frontal white matter area and left lateral ventricle posterior horn at the lateral ventricle posterior horn layer,images contrast-to-noise ratio(CNR),image quality score and specific absorption rate(SAR)were compared between different sequence images,and the scanning times were recorded.Results SNR of left frontal white matter area and left lateral ventricle posterior horn,as well as CNR of thick-layer negative-spacing B-FFE sequence images were higher than those of conventional slice-thickness and space B-FFE sequence images(Z=-8.290,-8.290,-8.013,all P<0.001).The image quality score of thick-layer negative-spacing B-FFE sequence was higher than that of conventional slice-thickness and space B-FFE sequence images(χ^(2)=10.966,P=0.004),while SAR were not different from conventional slice-thickness and space B-FFE sequence image(Z=-0.362,P=0.717).The acquisition time of thick-layer negative-spacing B-FFE sequence was 57 s,of conventional slice-thickness and space B-FFE sequence was 37 s.Conclusion Application of thick-layer negative-spacing technology in fetal head B-FFE sequence scanning could improve image quality and clearly show the fetal anatomy and the details of lesions.