目的:为了研究T1加权快速流体衰减反转恢复MRI序列的优势,无需(T1-FFLAIR)和压缩传感技术(T1-FFLAIR-CS),这显示了改善的T1加权对比度,超过标准的T1加权快速场回波(T1-FFE)序列用于评估胎儿髓鞘形成。
方法:这项回顾性单中心研究包括115个连续的胎儿脑MRI检查(63个轴向和76个冠状,平均胎龄(GA)28.56±5.23周,范围19-39周)。两个评估者,对GA视而不见,定性评估每个T1加权序列在五个大脑区域(延髓,pons,中脑,丘脑,中部地区)。一名评估者在相同的五个大脑区域进行了感兴趣区域定量分析(n=61)。在每个T1加权序列上,将Pearson相关性分析用于MTS和信号强度比(相对于肌肉)与GA的相关性。将基于胎儿MRI的结果与死后胎儿人脑的髓鞘形成模式进行了比较(n=46;GA18至42),通过组织学和免疫组织化学分析处理。
结果:MTS在所有三个序列上与GA呈正相关(所有r在0.802和0.908之间)。在五个大脑区域测得的信号强度比与T1-FFLAIR上的GA最佳相关(r在0.583和0.785之间)。在定性和定量分析中,T1-FFLAIR与GA的相关性明显优于T1-FFE(均p<0.05)。此外,与组织学相比,T1-FFLAIR可实现有髓脑结构的最佳可视化。
结论:T1-FFLAIR在胎儿脑髓鞘形成的可视化中优于标准T1-FFE序列,正如定性和定量方法所证明的那样。
结论:T1加权快速液体衰减反转恢复序列(T1-FFLAIR)提供了子宫内髓鞘形成的最佳可视化和定量,除了相对较短的采集时间外,使其在胎儿MRI中的常规应用能够评估脑髓鞘形成。
结论:•到目前为止,由于对比度不足,对子宫内胎儿髓鞘形成的评估受到限制。•T1加权的快速流体衰减反转恢复序列允许胎儿脑髓鞘形成的定性和定量评估。•T1加权的快速流体衰减反转恢复序列优于用于子宫内髓鞘形成的可视化和定量的标准T1加权序列。
OBJECTIVE: To investigate the advantage of T1-weighted fast fluid-attenuated inversion-recovery MRI sequence without (T1-FFLAIR) and with compressed sensing technology (T1-FFLAIR-CS), which shows improved T1-weighted contrast, over standard used T1-weighted fast field echo (T1-FFE) sequence for the assessment of fetal myelination.
METHODS: This retrospective single-center study included 115 consecutive fetal brain MRI examinations (63 axial and 76 coronal, mean gestational age (GA) 28.56 ± 5.23 weeks, range 19-39 weeks). Two raters, blinded to GA, qualitatively assessed a fetal myelin total score (MTS) on each T1-weighted sequence at five brain regions (medulla oblongata, pons, mesencephalon, thalamus, central region). One rater performed region-of-interest quantitative analysis (n = 61) at the same five brain regions. Pearson correlation analysis was applied for correlation of MTS and of the signal intensity ratios (relative to muscle) with GA on each T1-weighted sequence. Fetal MRI-based results were compared with myelination patterns of postmortem fetal human brains (n = 46; GA 18 to 42), processed by histological and immunohistochemical analysis.
RESULTS: MTS positively correlated with GA on all three sequences (all r between 0.802 and 0.908). The signal intensity ratios measured at the five brain regions correlated best with GA on T1-FFLAIR (r between 0.583 and 0.785). T1-FFLAIR demonstrated significantly better correlations with GA than T1-FFE for both qualitative and quantitative analysis (all p < 0.05). Furthermore, T1-FFLAIR enabled the best visualization of myelinated brain structures when compared to histology.
CONCLUSIONS: T1-FFLAIR outperforms the standard T1-FFE sequence in the visualization of fetal brain myelination, as demonstrated by qualitative and quantitative methods.
CONCLUSIONS: T1-weighted fast fluid-attenuated inversion-recovery sequence (T1-FFLAIR) provided best visualization and quantification of myelination in utero that, in addition to the relatively short acquisition time, makes feasible its routine application in fetal MRI for the assessment of brain myelination.
CONCLUSIONS: • So far, the assessment of fetal myelination in utero was limited due to the insufficient contrast. • T1-weighted fast fluid-attenuated inversion-recovery sequence allows a qualitative and quantitative assessment of fetal brain myelination. • T1-weighted fast fluid-attenuated inversion-recovery sequence outperforms the standard used T1-weighted sequence for visualization and quantification of myelination in utero.