arXiv:2508.14950eess.IVcs.LG2025-08

用GAN提升4D血流MRI的近壁速度分辨率,显著改善低信噪比下的图像质量。

Potential and challenges of generative adversarial networks for super-resolution in 4D Flow MRI

  • 设计专用GAN架构,对比三种对抗损失函数优化超分辨效果。
  • Wasserstein GAN在低信噪比下将速度误差降低至8.7%(基准10.7%)。
  • 适用于脑血管等复杂区域的高精度血流分析,适合医学影像研究者。

4D Flow MRI可无创量化血流与血流动力学参数,但其临床应用受限于空间分辨率低和噪声大,尤其影响近壁速度测量。基于机器学习的超分辨率技术有望解决此问题,但恢复近壁速度仍具挑战。生成对抗网络(GAN)在非医学超分辨任务中表现出优异的边界恢复能力,但在4D Flow MRI中尚未探索,且面临训练不稳定、不收敛等问题。本研究采用患者特异性脑血管体模,通过真实MR重建流程生成合成图像,构建专用GAN架构,并评估三种对抗损失:标准型、相对型和Wasserstein型。结果表明,所提GAN相比非对抗基线(vNRMSE:6.9% vs. 9.6%)显著提升了近壁速度恢复;其中Wasserstein GAN表现最优且最稳定(vNRMSE:6.9% vs. 7.2%),在低信噪比下优于基线(8.7% vs. 10.7%)。研究证实了GAN在增强4D Flow MRI中的潜力,尤其在复杂脑血管区域,同时强调需谨慎选择对抗策略。

原文摘要 · Abstract (English)

4D Flow Magnetic Resonance Imaging (4D Flow MRI) enables non-invasive quantification of blood flow and hemodynamic parameters. However, its clinical application is limited by low spatial resolution and noise, particularly affecting near-wall velocity measurements. Machine learning-based super-resolution has shown promise in addressing these limitations, but challenges remain, not least in recovering near-wall velocities. Generative adversarial networks (GANs) offer a compelling solution, having demonstrated strong capabilities in restoring sharp boundaries in non-medical super-resolution tasks. Yet, their application in 4D Flow MRI remains unexplored, with implementation challenged by known issues such as training instability and non-convergence. In this study, we investigate GAN-based super-resolution in 4D Flow MRI. Training and validation were conducted using patient-specific cerebrovascular in-silico models, converted into synthetic images via an MR-true reconstruction pipeline. A dedicated GAN architecture was implemented and evaluated across three adversarial loss functions: Vanilla, Relativistic, and Wasserstein. Our results demonstrate that the proposed GAN improved near-wall velocity recovery compared to a non-adversarial reference (vNRMSE: 6.9% vs. 9.6%); however, that implementation specifics are critical for stable network training. While Vanilla and Relativistic GANs proved unstable compared to generator-only training (vNRMSE: 8.1% and 7.8% vs. 7.2%), a Wasserstein GAN demonstrated optimal stability and incremental improvement (vNRMSE: 6.9% vs. 7.2%). The Wasserstein GAN further outperformed the generator-only baseline at low SNR (vNRMSE: 8.7% vs. 10.7%). These findings highlight the potential of GAN-based super-resolution in enhancing 4D Flow MRI, particularly in challenging cerebrovascular regions, while emphasizing the need for careful selection of adversarial strategies.

超分辨率GAN4D Flow MRI血流分析

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