multiGradICON: A Foundation Model for Multimodal Medical Image Registration
Basar Demir, Lin Tian, Thomas Hastings Greer, Roland Kwitt, Francois-Xavier Vialard, Raul San Jose Estepar, Sylvain Bouix, Richard Jarrett Rushmore, Ebrahim Ebrahim, Marc Niethammer
TL;DR
multiGradICON tackles universal multimodal medical image registration by extending the uniGradICON framework with a multimodal similarity measure and training-time loss randomization across modalities. It adopts the GradICON architectural paradigm with a multi-resolution TS/DS pipeline and trains on a large, diverse corpus spanning 16 datasets, 5 anatomical regions, and 12 modalities, using a $1-\text{LNCC}^2$ loss to handle sign-ambiguous multimodal correlations. The results show that multiGradICON retains strong monomodal performance while achieving pronounced improvements in multimodal registration, particularly when employing loss-randomization strategies, with ROI-focused training further boosting lung registrations; some challenging cross-modality pairs (e.g., DIXON fat–water) remain difficult and may benefit from segmentation-based losses. The work positions multiGradICON as a foundation-model-style approach to broad cross-modality alignment in medical imaging, enabling broader generalization across anatomies and imaging modalities, and it provides public code to foster accessibility and further research.
Abstract
Modern medical image registration approaches predict deformations using deep networks. These approaches achieve state-of-the-art (SOTA) registration accuracy and are generally fast. However, deep learning (DL) approaches are, in contrast to conventional non-deep-learning-based approaches, anatomy-specific. Recently, a universal deep registration approach, uniGradICON, has been proposed. However, uniGradICON focuses on monomodal image registration. In this work, we therefore develop multiGradICON as a first step towards universal *multimodal* medical image registration. Specifically, we show that 1) we can train a DL registration model that is suitable for monomodal *and* multimodal registration; 2) loss function randomization can increase multimodal registration accuracy; and 3) training a model with multimodal data helps multimodal generalization. Our code and the multiGradICON model are available at https://github.com/uncbiag/uniGradICON.
