ADDG: An Adaptive Domain Generalization Framework for Cross-Plane MRI Segmentation

Multi-planar magnetic resonance imaging (MRI) can provide comprehensive 3D structural information for disease diagnosis. Compared to multi-source MRI, multi-planar MRI scans target areas in the human body from different directions. This atypical difference between directions may lead to poor performance of traditional domain generalization methods, especially when MRI from different planes also comes from different sources. In this paper, we propose ADDG, an Adaptive Domain Generalization framework for accurate cross-plane MRI segmentation. ADDG significantly mitigates the impact of information loss caused by slice spacing by injecting 3D shape prior to the segmentation target and capturing domain-agnostic feature differences from heterogeneous data sources through an adaptive data partitioning strategy. In addition, we propose a mesh deformation-based organ segmentation network to simultaneously delineate 2D boundary and 3D volume of organ, which could guide more accurate mesh deformation. We also develop an organ-specific mesh template and employ Loop subdivision for generating smoother 3D organ mesh. Furthermore, we design a flexible meta-learning paradigm to adaptively partition data domains based on invariant learning, which can learn domain-agnostic features from multi-source data to enhance the overall generalization ability. Experimental results show that ADDG outperforms several medical image segmentation, single-view 3D shape reconstruction, and domain generalization methods.