多尺度结构引导的潜在扩散模型用于多模态MRI翻译
Multiscale Structure-Guided Latent Diffusion for Multimodal MRI Translation
AI总结:
本文提出MSG-LDM框架,通过多尺度特征空间分离风格与结构信息,提升多模态MRI翻译的结构一致性与纹理细节。
摘要:
尽管扩散模型在多模态MRI翻译任务中取得了显著进展,但现有方法在处理任意缺失模态场景时仍面临解剖不一致或纹理细节退化的问题。为此,我们提出了一种基于潜在扩散的多模态MRI翻译框架MSG-LDM。通过利用可用模态,该方法推断出完整的结构信息,保持可靠的边界细节。具体而言,我们引入了潜在空间中的风格-结构解耦机制,将模态特定的风格特征与共享的结构表示显式分离,并在多尺度特征空间中联合建模低频解剖布局和高频边界细节。在结构解耦阶段,高频率的结构信息被显式纳入以增强特征表示,引导模型关注细粒度的结构线索,同时学习模态不变的低频解剖表示。此外,为了减少模态特定风格的干扰并提高结构表示的稳定性,我们设计了风格一致性损失和结构感知损失。在BraTS2020和WMH数据集上的大量实验表明,所提方法在重构完整结构方面优于现有MRI合成方法。源代码可在https://github.com/ziyi-start/MSG-LDM上公开获取。
英文摘要:
Although diffusion models have achieved remarkable progress in multi-modal magnetic resonance imaging (MRI) translation tasks, existing methods still tend to suffer from anatomical inconsistencies or degraded texture details when handling arbitrary missing-modality scenarios. To address these issues, we propose a latent diffusion-based multi-modal MRI translation framework, termed MSG-LDM. By leveraging the available modalities, the proposed method infers complete structural information, which preserves reliable boundary details. Specifically, we introduce a style--structure disentanglement mechanism in the latent space, which explicitly separates modality-specific style features from shared structural representations, and jointly models low-frequency anatomical layouts and high-frequency boundary details in a multi-scale feature space. During the structure disentanglement stage, high-frequency structural information is explicitly incorporated to enhance feature representations, guiding the model to focus on fine-grained structural cues while learning modality-invariant low-frequency anatomical representations. Furthermore, to reduce interference from modality-specific styles and improve the stability of structure representations, we design a style consistency loss and a structure-aware loss. Extensive experiments on the BraTS2020 and WMH datasets demonstrate that the proposed method outperforms existing MRI synthesis approaches, particularly in reconstructing complete structures. The source code is publicly available at https://github.com/ziyi-start/MSG-LDM.
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