Fetal Magnetic Resonance Imaging (MRI) is an important noninvasive diagnostic tool to characterize the central nervous system (CNS) development, significantly contributing to pregnancy management. In clinical practice, fetal MRI of the brain includes the acquisition of fast anatomical sequences over different planes on which several biometric measurements are manually extracted. Recently, modern toolkits use the acquired two-dimensional (2D) images to reconstruct a Super-Resolution (SR) isotropic volume of the brain, enabling three-dimensional (3D) analysis of the fetal CNS.

We analyzed 17 fetal MR exams performed in the second trimester, including orthogonal T2-weighted (T2w) Turbo Spin Echo (TSE) and balanced Fast Field Echo (b-FFE) sequences. For each subject and type of sequence, three distinct high-resolution volumes were reconstructed via NiftyMIC, MIALSRTK, and SVRTK toolkits. Fifteen biometric measurements were assessed both on the acquired 2D images and SR reconstructed volumes, and compared using Passing-Bablok regression, Bland-Altman plot analysis, and statistical tests.

Results indicate that NiftyMIC and MIALSRTK provide reliable SR reconstructed volumes, suitable for biometric assessments. NiftyMIC also improves the operator intraclass correlation coefficient on the quantitative biometric measures with respect to the acquired 2D images. In addition, TSE sequences lead to more robust fetal brain reconstructions against intensity artifacts compared to b-FFE sequences, despite the latter exhibiting more defined anatomical details.

Our findings strengthen the adoption of automatic toolkits for fetal brain reconstructions to perform biometry evaluations of fetal brain development over common clinical MR at an early pregnancy stage.

胎儿磁共振成像 (MRI) 是一种重要的无创诊断工具，可表征中枢神经系统 (CNS) 发育，对妊娠管理有显着贡献。在临床实践中，胎儿大脑 MRI 包括采集不同平面上的快速解剖序列，并手动提取多个生物测量值。最近，现代工具包使用获取的二维 (2D) 图像来重建大脑的超分辨率 (SR) 各向同性体积，从而能够对胎儿中枢神经系统进行三维 (3D) 分析。

我们分析了在妊娠中期进行的 17 次胎儿 MR 检查，包括正交 T2 加权 (T2w) 涡轮自旋回波 (TSE) 和平衡快速场回波 (b-FFE) 序列。对于每个受试者和序列类型，通过 NiftyMIC、MIALSRTK 和 SVRTK 工具包重建了三个不同的高分辨率体积。对采集的 2D 图像和 SR 重建体积评估了 15 项生物测量测量值，并使用 Passing-Bablok 回归、Bland-Altman 图分析和统计测试进行比较。

结果表明 NiftyMIC 和 MIALSRTK 提供可靠的 SR 重建体积，适合生物识别评估。NiftyMIC 还改进了与所采集的 2D 图像有关的定量生物特征测量的操作员组内相关系数。此外，与 b-FFE 序列相比，TSE 序列可以针对强度伪影进行更稳健的胎儿大脑重建，尽管后者表现出更明确的解剖细节。

我们的研究结果加强了胎儿大脑重建自动工具包的采用，以对妊娠早期阶段常见的临床 MR 进行胎儿大脑发育的生物测定评估。