Snoussi Haykel, Karimi Davood, Afacan Onur, Utkur Mustafa, Gholipour Ali
Boston Children's Hospital, and Harvard Medical School, Boston, MA 02115 USA.
ArXiv. 2024 Jun 28:arXiv:2406.20042v1.
Diffusion magnetic resonance imaging (dMRI) is pivotal for probing the microstructure of the rapidly-developing fetal brain. However, fetal motion during scans and its interaction with magnetic field inhomogeneities result in artifacts and data scattering across spatial and angular domains. The effects of those artifacts are more pronounced in high-angular resolution fetal dMRI, where signal-to-noise ratio is very low. Those effects lead to biased estimates and compromise the consistency and reliability of dMRI analysis. This work presents HAITCH, the first and the only publicly available tool to correct and reconstruct multi-shell high-angular resolution fetal dMRI data. HAITCH offers several technical advances that include a blip-reversed dual-echo acquisition for dynamic distortion correction, advanced motion correction for and robust reconstruction, optimized multi-shell design for enhanced information capture and increased tolerance to motion, and outlier detection for improved reconstruction fidelity. The framework is open-source, flexible, and can be used to process any type of fetal dMRI data including single-echo or single-shell acquisitions, but is most effective when used with multi-shell multi-echo fetal dMRI data that cannot be processed with any of the existing tools. Validation experiments on real fetal dMRI scans demonstrate significant improvements and accurate correction across diverse fetal ages and motion levels. HAITCH successfully removes artifacts and reconstructs high-fidelity fetal dMRI data suitable for advanced diffusion modeling, including fiber orientation distribution function estimation. These advancements pave the way for more reliable analysis of the fetal brain microstructure and tractography under challenging imaging conditions.
扩散磁共振成像（dMRI）对于探究快速发育的胎儿大脑的微观结构至关重要。然而，扫描过程中胎儿的运动及其与磁场不均匀性的相互作用会导致伪影，并使数据在空间和角度域中散射。在高角分辨率胎儿dMRI中，这些伪影的影响更为明显，因为其信噪比非常低。这些影响会导致估计偏差，并损害dMRI分析的一致性和可靠性。这项工作提出了HAITCH，这是第一个也是唯一公开可用的工具，用于校正和重建多壳高角分辨率胎儿dMRI数据。HAITCH提供了多项技术进步，包括用于动态失真校正的反转回波双回波采集、用于稳健重建的先进运动校正、用于增强信息捕获和提高运动耐受性的优化多壳设计，以及用于提高重建保真度的异常值检测。该框架是开源的、灵活的，可用于处理任何类型的胎儿dMRI数据，包括单回波或单壳采集，但与现有的任何工具都无法处理的多壳多回波胎儿dMRI数据一起使用时最为有效。对真实胎儿dMRI扫描的验证实验表明，在不同胎儿年龄和运动水平下都有显著改善和准确校正。HAITCH成功地去除了伪影，并重建了适用于高级扩散建模（包括纤维取向分布函数估计）的高保真胎儿dMRI数据。这些进展为在具有挑战性的成像条件下更可靠地分析胎儿大脑微观结构和纤维束成像铺平了道路。
