arXiv:2504.07308eess.IVcs.CV2025-04被引 4

用专家协作的扩散模型,让脑部MRI图像不同区域自动优化清晰度。

MoEDiff-SR: Mixture of Experts-Guided Diffusion Model for Region-Adaptive MRI Super-Resolution

  • 通过门控网络动态选择不同专家,按区域特点分治图像修复。
  • 在多个指标上超越现有方法,尤其在细小病灶识别上表现更优。
  • 适合临床神经影像分析,结果可解释性强,便于医生信任使用。

低场强磁共振成像(如3T)存在空间分辨率有限的问题,难以捕捉精细解剖结构,影响临床诊断与神经影像研究。为此,本文提出MoEDiff-SR,一种基于混合专家(MoE)引导的扩散模型,实现区域自适应的MRI超分辨率重建。不同于传统扩散模型对全图统一去噪,MoEDiff-SR在细粒度令牌级别动态选择专用去噪专家,确保各区域特性得到针对性处理。具体而言,先通过基于Transformer的特征提取器生成多尺度块嵌入,捕获全局结构与局部纹理;再输入到MoE门控网络,为多个专注于不同脑区特征的扩散去噪器分配自适应权重,如半卵圆中心、沟回皮层及灰白质交界处。最终输出由各专家去噪结果按动态门控概率加权融合。实验表明,该方法在定量指标、感知保真度和计算效率上均优于当前最优方法。各专家的差异图进一步验证其专长分化,证明了区域自适应去噪的有效性与贡献可解释性。临床评估也证实其在识别微小病理特征方面具备更强诊断能力,凸显其在临床神经影像中的实际价值。代码已公开于https://github.com/ZWang78/MoEDiff-SR。

原文摘要 · Abstract (English)

Magnetic Resonance Imaging (MRI) at lower field strengths (e.g., 3T) suffers from limited spatial resolution, making it challenging to capture fine anatomical details essential for clinical diagnosis and neuroimaging research. To overcome this limitation, we propose MoEDiff-SR, a Mixture of Experts (MoE)-guided diffusion model for region-adaptive MRI Super-Resolution (SR). Unlike conventional diffusion-based SR models that apply a uniform denoising process across the entire image, MoEDiff-SR dynamically selects specialized denoising experts at a fine-grained token level, ensuring region-specific adaptation and enhanced SR performance. Specifically, our approach first employs a Transformer-based feature extractor to compute multi-scale patch embeddings, capturing both global structural information and local texture details. The extracted feature embeddings are then fed into an MoE gating network, which assigns adaptive weights to multiple diffusion-based denoisers, each specializing in different brain MRI characteristics, such as centrum semiovale, sulcal and gyral cortex, and grey-white matter junction. The final output is produced by aggregating the denoised results from these specialized experts according to dynamically assigned gating probabilities. Experimental results demonstrate that MoEDiff-SR outperforms existing state-of-the-art methods in terms of quantitative image quality metrics, perceptual fidelity, and computational efficiency. Difference maps from each expert further highlight their distinct specializations, confirming the effective region-specific denoising capability and the interpretability of expert contributions. Additionally, clinical evaluation validates its superior diagnostic capability in identifying subtle pathological features, emphasizing its practical relevance in clinical neuroimaging. Our code is available at https://github.com/ZWang78/MoEDiff-SR.

MRI超分辨扩散模型专家系统神经影像

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