Centre for the Developing Brain, Division of Imaging Sciences and Biomedical Engineering, King's College London, King's Health Partners, St. Thomas' Hospital, London, SE1 7EH, UK.
Robert Steiner Unit, Imaging Sciences Department, MRC Clinical Sciences Centre, Hammersmith Hospital, Imperial College London, London, W12 0HS, UK.
MAGMA. 2019 Aug;32(4):473-485. doi: 10.1007/s10334-019-00743-5. Epub 2019 Mar 12.
Fetal brain diffusion tensor imaging (DTI) offers quantitative analysis of the developing brain. The objective was to 1) quantify DTI measures across gestation in a cohort of fetuses without brain abnormalities using full retrospective correction for fetal head motion 2) compare results obtained in utero to those in preterm infants.
Motion-corrected DTI analysis was performed on data sets obtained at 1.5T from 32 fetuses scanned between 21.29 and 37.57 (median 31.86) weeks. Results were compared to 32 preterm infants scanned at 3T between 27.43 and 37.14 (median 33.07) weeks. Apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were quantified by region of interest measurements and tractography was performed.
Fetal DTI was successful in 84% of fetuses for whom there was sufficient data for DTI estimation, and at least one tract could be obtained in 25 cases. Fetal FA values increased and ADC values decreased with age at scan (PLIC FA: p = 0.001; R = 0.469; slope = 0.011; splenium FA: p < 0.001; R = 0.597; slope = 0.019; thalamus ADC: p = 0.001; R = 0.420; slope = - 0.023); similar trends were found in preterm infants.
This study demonstrates that stable DTI is feasible on fetuses and provides evidence for normative values of diffusion properties that are consistent with aged matched preterm infants.
胎儿脑弥散张量成像（DTI）可对发育中的大脑进行定量分析。本研究旨在：1）使用全回顾性校正胎儿头部运动，对无脑异常胎儿的整个妊娠期的 DTI 测量值进行量化；2）比较在宫内获得的结果与早产儿的结果。
对在 1.5T 扫描仪上获得的 32 例胎龄在 21.29 至 37.57 周（中位数 31.86 周）的胎儿的数据进行运动校正的 DTI 分析。将结果与在 3T 扫描仪上获得的胎龄在 27.43 至 37.14 周（中位数 33.07 周）的 32 例早产儿进行比较。通过感兴趣区测量法对表观弥散系数（ADC）和各向异性分数（FA）进行量化，并进行了纤维束追踪。
84%的胎儿有足够的数据进行 DTI 估计，并且在 25 例中至少可以获得一条纤维束。FA 值随扫描时的年龄而增加，ADC 值随年龄而降低（PLIC FA：p = 0.001；R = 0.469；斜率= 0.011；胼胝体 FA：p < 0.001；R = 0.597；斜率= 0.019；丘脑 ADC：p = 0.001；R = 0.420；斜率= - 0.023）；早产儿也有类似的趋势。
本研究表明，在胎儿中进行稳定的 DTI 是可行的，并为与年龄匹配的早产儿相一致的扩散特性的正常数值提供了证据。
