Corroenne R, Papastefanou I, Mahallati H, Bobet L, Bussieres L, Grevent D, Salomon L J
Plateforme LUMIERE, URP FETUS 7328, Fédération pour la Recherche en Explorations et Thérapeutiques Innovantes In Utero, Equipe Associée à l'Institut IMAGINE, Université Paris Cité, Paris, France.
Department of Women and Children's Health, School of Life Course and Population Sciences, Faculty of Life Sciences and Medicine, King's College London, London, UK.
Ultrasound Obstet Gynecol. 2025 Jul 3. doi: 10.1002/uog.29275.
Diffusion tensor imaging (DTI) of the fetal brain can generate unique quantitative data that reflect both tissue integrity and the level of myelination in the developing brain. The objective of this study was to quantify normal fetal brain metrics from 21 to 36 weeks' gestation using DTI in a cohort of healthy fetuses, using the latest techniques designed to minimize artifacts from movement and those inherent to magnetic resonance imaging (MRI) acquisition.
We conducted a prospective study between June 2021 and June 2022 of pregnant volunteers with no known fetal anomalies, between 21 and 36 weeks' gestation. MRI scans were performed using a 1.5-T 450W General Electric Signa MRI system, including 15 non-collinear diffusion-weighted axial images of the fetal brain. Preprocessing included denoising, correction of Gibb's ringing artifact, eddy current correction, bias removal, registration to a reference template, slice-to-volume reconstruction and constrained spherical convolution to obtain maps of fractional anisotropy (FA), apparent diffusion coefficient (ADC), axial diffusivity (AD) and radial diffusivity (RD). A total of 51 white matter and gray matter regions from both hemispheres were analyzed. Regression models were used to describe the evolution of the DTI metrics during gestation.
DTI was successful in 94/111 (84.7%) fetuses and was performed at a median of 30 (range, 21-36) weeks' gestation. In the different white matter tracts, FA showed five distinct patterns: (1) initial decrease until 32-34 weeks, followed by an increase until 36 weeks; (2) initial decrease until 25-26 weeks, followed by an increase until 36 weeks; (3) linear increase; (4) linear decrease; or (5) no gestational-age-related change. In the different gray matter regions, FA showed three distinct patterns: (1) linear decrease; (2) initial decrease until 31-34 weeks, followed by an increase; or (3) no gestational-age-related change. In the majority of white matter and gray matter regions, ADC, AD and RD showed a linear decrease between 21 and 36 weeks.
The variations in DTI metrics may indirectly reflect the microstructural changes that occur during brain development, particularly during myelination, and may help characterize the development of fetal brain connectivity in utero. © 2025 International Society of Ultrasound in Obstetrics and Gynecology.
胎儿脑扩散张量成像（DTI）能够生成独特的定量数据，反映发育中脑的组织完整性和髓鞘形成水平。本研究的目的是在一组健康胎儿中，使用旨在将运动伪影以及磁共振成像（MRI）采集固有的伪影降至最低的最新技术，通过DTI对妊娠21至36周的正常胎儿脑指标进行量化。
我们在2021年6月至2022年6月期间对妊娠21至36周、无已知胎儿异常的孕妇志愿者进行了一项前瞻性研究。使用1.5-T 450W通用电气Signa MRI系统进行MRI扫描，包括15张胎儿脑的非共线扩散加权轴向图像。预处理包括去噪、吉布斯振铃伪影校正、涡流校正、偏差去除、配准到参考模板、切片到体积重建以及约束球形卷积，以获得分数各向异性（FA）、表观扩散系数（ADC）、轴向扩散率（AD）和径向扩散率（RD）图。对来自两个半球的总共51个白质和灰质区域进行了分析。使用回归模型描述妊娠期间DTI指标的演变。
DTI在94/111（84.7%）的胎儿中成功完成，中位妊娠周数为30周（范围21 - 36周）。在不同的白质束中，FA呈现出五种不同的模式：（1）最初下降至32 - 34周，随后上升至36周；（2）最初下降至25 - 26周，随后上升至36周；（3）线性上升；（4）线性下降；或（5）与胎龄无关的变化。在不同的灰质区域，FA呈现出三种不同的模式：（1）线性下降；（2）最初下降至31 - 34周，随后上升；或（3）与胎龄无关的变化。在大多数白质和灰质区域，ADC、AD和RD在21至36周之间呈线性下降。
DTI指标的变化可能间接反映脑发育过程中发生的微观结构变化，尤其是在髓鞘形成期间，并可能有助于描述子宫内胎儿脑连接性的发育。© 2025国际妇产科超声学会。
