3D in utero quantification of T2* relaxation times in human fetal brain tissues for age optimized structural and functional MRI.
3D in utero quantification of T2* relaxation times in human fetal brain tissues for age optimized structural and functional MRI.
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DOI：
10.1002/mrm.26471
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发表时间：
2017-09
影响因子：
3.3
通讯作者：
Studholme C
中科院分区：
文献类型：
--
作者：
Blazejewska AI;Seshamani S;McKown SK;Caucutt JS;Dighe M;Gatenby C;Studholme C
要最大化大胆的fMRI对比度，需要MR序列的TE与感兴趣组织的T2*值匹配，与儿童或成人相比，胎儿大脑中的T2*值预计会更高。从妊娠中期(20-36GW)开始，使用2D双回声T2*-w数据计算的3D T2*图，以及1.0mm3各向同性分辨率的T2-w结构数据，测量了自妊娠中期(20-36GW)起的健康胎儿子宫内皮质板/皮质灰质组织的T2*值。皮质组织的平均T2*松弛时间大约是先前报道的成年人的两倍。在支持性的单种子分析实验中，当TE=100ms与TE=43ms时，默认模式和听觉网络显示出更好的局部化和更低的噪声。先前报告T2*值随胎龄下降的研究结果被复制并扩展到包括早期妊娠(20-26GW)和皮质组织的受试者。首次对胎儿皮质组织中T2*值的测量表明，胎儿BOLD功能磁共振成像方案优化的合适TE范围为130-190ms。
Maximization of the BOLD fMRI contrast requires TE of the MR sequence to match the T2* value of the tissue of interest, which is expected to be higher in the fetal brain compared to a child or an adult. T2* values of the cortical plate/cortical grey matter tissue in utero in healthy fetuses from mid-gestation onwards (20–36 GW) were measured using 3D T2* maps calculated from 2D dual-echo T2*-w data corrected for between-slice motion and reconstructed in 1.0 mm3 isotropic resolution from a sequence of multiple time points, together with 1.0 mm3 isotropic resolution T2-w structural data. Mean T2* relaxation times of the cortical tissue were about two times higher than previously reported in adults. In a supporting single seed analysis experiment default mode and auditory networks appeared better localized and less noisy while using TE=100 ms versus TE=43 ms. The results of the previous study reporting a trend for T2* values to decrease with fetal age were reproduced and extended to include subjects in earlier gestation (20–26 GW) and cortical tissues. The first measurement of T2* values in fetal cortical tissues suggested the appropriate TE range for fetal BOLD fMRI protocol optimization to be 130–190 ms.