Treating missing modalities as uncertainty: SIUM reaches average Dice of 88.07/87.10/62.52 on BraTS 2018/2020 under missing-modality settings
The work proposes SIUM, which models each modality subset's task representation as a Gaussian (mean carrying task information, variance measuring uncertainty from missing evidence), aligns subset means toward a full-modality anchor via an uncertainty-aware alignment loss that scales variance with their discrepancy, and adds an uncertainty ordering loss keeping subset variance above its supersets, achieving better segmentation than RFNet, mmFormer, M3AE, and DC-Seg across diverse missing-modality configurations on BraTS 2018 and 2020.