A spatiotemporal fetal MRI atlas for multi-organ segmentation and growth analysis

We propose a comprehensive framework for spatiotemporal multi-organ fetal MR atlasing and segmentation. Volumetric fetal brain and trunk image data for 78 healthy fetuses acquired at different gestational age were reconstructed separately from motion corrupted MRI scans to 0.75mm isotropic resolution using slice-to-volume reconstruction. For each week, an affine template was generated from 15 subjects by averaging them in the atlas space. This template was further improved by non-linear registration of all the subjects using B-spline free-form deformations. For consistency, the template at each week was rigidly transformed. The annotated organs of the atlas include brain, lung, heart, and spine.