用解耦嵌入实现MRI运动伪影的通用修正,无需针对特定伪影训练。
Retrospective motion correction in MRI using disentangled embeddings
- 通过分层向量量化VAE学习运动与清晰图像特征的解耦表示。
- 在模拟全身运动伪影上实现跨严重程度的鲁棒修正,无需重新训练。
- 适用于多种解剖区域和运动类型,提升ML方法的泛化能力。
生理运动会影响磁共振成像(MRI)的诊断质量。尽管已有多种回顾性运动校正方法,但许多难以在不同运动类型和身体部位间泛化,尤其机器学习方法常针对特定应用和数据集定制。我们假设,尽管运动伪影多样,但其背后存在可解耦的共同模式。为此,提出一种分层向量量化(VQ)变分自编码器,学习运动-清晰图像特征的解耦嵌入。通过码本在多分辨率下捕捉有限的运动模式集合,实现粗到细的修正。训练自回归模型以学习无运动图像的先验分布,并在推理时引导校正过程。与传统方法不同,该方法无需针对伪影特异性训练,可泛化至未见过的运动模式。我们在模拟全身运动伪影上验证了该方法,在不同运动严重程度下均表现稳健。结果表明,模型有效解耦了模拟运动有效扫描中的物理运动特征,从而提升了基于机器学习的MRI运动校正的泛化能力。本工作为解耦运动特征在跨解剖区域和运动类型的潜在应用提供了新思路。
原文摘要 · Abstract (English)
Physiological motion can affect the diagnostic quality of magnetic resonance imaging (MRI). While various retrospective motion correction methods exist, many struggle to generalize across different motion types and body regions. In particular, machine learning (ML)-based corrections are often tailored to specific applications and datasets. We hypothesize that motion artifacts, though diverse, share underlying patterns that can be disentangled and exploited. To address this, we propose a hierarchical vector-quantized (VQ) variational auto-encoder that learns a disentangled embedding of motion-to-clean image features. A codebook is deployed to capture finite collection of motion patterns at multiple resolutions, enabling coarse-to-fine correction. An auto-regressive model is trained to learn the prior distribution of motion-free images and is used at inference to guide the correction process. Unlike conventional approaches, our method does not require artifact-specific training and can generalize to unseen motion patterns. We demonstrate the approach on simulated whole-body motion artifacts and observe robust correction across varying motion severity. Our results suggest that the model effectively disentangled physical motion of the simulated motion-effective scans, therefore, improving the generalizability of the ML-based MRI motion correction. Our work of disentangling the motion features shed a light on its potential application across anatomical regions and motion types.
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