A Unified Degradation-Robust Approach to SSL and UDA for 3D Medical Images

Medical image segmentation often faces the dual challenges of limited annotations and domain shifts, further complicated by degraded images in practical scenarios. Traditional methods tend to underperform when these issues occur simultaneously, as they are typically designed for specific tasks. To address this, we propose a unified framework that effectively handles limited annotations and domain shifts while also managing both clean and degraded images during inference. Overcoming these challenges requires focusing on three critical aspects: First, the model must be robust to various noise conditions. Second, it should excel at capturing domain-invariant features. Third, it should effectively utilize unlabeled data. We propose three major components in our approach to tackle these challenges. First, the Wavelet-based Cross-Component Exchange (WCCE) swaps high-frequency wavelet components between labeled and unlabeled images to enhance robustness. Second, we employ a diffusion VNet architecture with a reweighting mechanism to capture domain-invariant features. Finally, we utilize Cross-Decoder Pseudo (CDP) training to effectively leverage unlabeled data. Evaluations on three publicly available medical datasets and across four types of degraded image scenarios demonstrate that our method outperforms state-of-the-art (SOTA) techniques, consistently delivering superior performance across varying image qualities. Our approach not only addresses annotation scarcity and domain shift but also effectively manages noisy and blurred conditions, setting a new benchmark in medical image segmentation.