Point2SSM++: Self-supervised learning of anatomical shape models from point clouds

Correspondence-based statistical shape modeling (SSM) stands as a powerful technology for morphometric analysis in clinical research. SSM facilitates population-level characterization and quantification of anatomical shapes such as bones and organs, aiding in pathology and disease diagnostics and treatment planning. Despite its potential, SSM remains under-utilized in medical research due to the significant overhead associated with automatic construction methods, which demand complete, aligned shape surface representations. Additionally, optimization-based techniques rely on bias-inducing assumptions or templates and have prolonged inference times as the entire cohort is simultaneously optimized. To overcome these challenges, we introduce Point2SSM++, a principled, self-supervised deep learning approach that directly learns correspondence points from point cloud representations of anatomical shapes. Point2SSM++ is robust to misaligned and inconsistent input, providing SSM that accurately samples individual shape surfaces while effectively capturing population-level statistics. Furthermore, we present extensions of Point2SSM++ tailored for dynamic spatiotemporal and multi-anatomy scenarios, showcasing the broad versatility of the framework. Through extensive validation across diverse anatomies, evaluation metrics, and clinically relevant downstream tasks, we demonstrate Point2SSM++’s superiority over existing state-of-the-art deep learning models and the traditional approach. Point2SSM++ substantially enhances the feasibility of SSM generation and significantly broadens its array of potential clinical applications. • Self-supervised approach for predicting anatomical correspondences from point clouds. • Outperforms statistical shape modeling methods on bones and organ populations. • Validation on downstream clinical tasks: craniosynostosis and femur pathology. • Extends to multi-anatomy learning such as full spine vertebrae. • Extends to 4D spatiotemporal data for longitudinal studies and dynamic shape analysis.