FetDTIAlign: A Deep Learning Framework for Affine and Deformable Registration of Fetal Brain dMRI
This work addresses the problem of accurate registration for fetal brain dMRI studies, enabling better cross-subject and tract-specific analyses in early neurodevelopment research.
The paper tackles the challenge of precise spatial alignment in fetal brain diffusion MRI (dMRI) scans, which is difficult due to low data quality and rapid development, by introducing FetDTIAlign, a deep learning framework that outperformed existing methods in anatomical correspondence across 60 white matter tracts from 23 to 36 weeks gestation.
Diffusion MRI (dMRI) provides unique insights into fetal brain microstructure in utero. Longitudinal and cross-sectional fetal dMRI studies can reveal crucial neurodevelopmental changes but require precise spatial alignment across scans and subjects. This is challenging due to low data quality, rapid brain development, and limited anatomical landmarks. Existing registration methods, designed for high-quality adult data, struggle with these complexities. To address this, we introduce FetDTIAlign, a deep learning approach for fetal brain dMRI registration, enabling accurate affine and deformable alignment. FetDTIAlign features a dual-encoder architecture and iterative feature-based inference, reducing the impact of noise and low resolution. It optimizes network configurations and domain-specific features at each registration stage, enhancing both robustness and accuracy. We validated FetDTIAlign on data from 23 to 36 weeks gestation, covering 60 white matter tracts. It consistently outperformed two classical optimization-based methods and a deep learning pipeline, achieving superior anatomical correspondence. Further validation on external data from the Developing Human Connectome Project confirmed its generalizability across acquisition protocols. Our results demonstrate the feasibility of deep learning for fetal brain dMRI registration, providing a more accurate and reliable alternative to classical techniques. By enabling precise cross-subject and tract-specific analyses, FetDTIAlign supports new discoveries in early brain development.