arXiv:2511.20081cs.CV2025-11被引 1

提出自适应局部去噪方法,提升化学位移交换谱成像的信噪比与定量精度。

Blind Adaptive Local Denoising for CEST Imaging

  • 利用自相似性构建可变稳态变换,自动适应复杂噪声分布。
  • 两阶段去噪在保持分子信号的同时显著降低噪声,提升定量图准确性。
  • 适用于临床CET成像,尤其适合癌症检测与代谢物浓度分析。

化学位移交换饱和转移(CEST)MRI通过质子交换动态实现低浓度代谢物的分子级可视化。然而,其临床应用受限于硬件限制导致的空间异质性噪声,以及复杂成像协议引发的数据异方差性,干扰了定量对比度映射(如酰胺质子转移,APT)的准确性。传统去噪方法不适用于此类复杂噪声,常扭曲关键生物信息。为此,本文提出盲自适应局部去噪(BALD)方法。BALD利用CEST数据的自相似性,构建无需先验噪声知识的自适应方差稳定变换,均衡各像素噪声分布;随后在数据的局部SVD线性变换上实施两阶段去噪,分离分子信号与噪声。实验在多类模型及活体CEST扫描中验证,BALD在去噪指标与下游任务(如分子浓度图估计、癌症检测)中持续优于现有最优方法。

原文摘要 · Abstract (English)

Chemical Exchange Saturation Transfer (CEST) MRI enables molecular-level visualization of low-concentration metabolites by leveraging proton exchange dynamics. However, its clinical translation is hindered by inherent challenges: spatially varying noise arising from hardware limitations, and complex imaging protocols introduce heteroscedasticity in CEST data, perturbing the accuracy of quantitative contrast mapping such as amide proton transfer (APT) imaging. Traditional denoising methods are not designed for this complex noise and often alter the underlying information that is critical for biomedical analysis. To overcome these limitations, we propose a new Blind Adaptive Local Denoising (BALD) method. BALD exploits the self-similar nature of CEST data to derive an adaptive variance-stabilizing transform that equalizes the noise distributions across CEST pixels without prior knowledge of noise characteristics. Then, BALD performs two-stage denoising on a linear transformation of data to disentangle molecular signals from noise. A local SVD decomposition is used as a linear transform to prevent spatial and spectral denoising artifacts. We conducted extensive validation experiments on multiple phantoms and \textit{in vivo} CEST scans. In these experiments, BALD consistently outperformed state-of-the-art CEST denoisers in both denoising metrics and downstream tasks such as molecular concentration maps estimation and cancer detection.

CEST成像去噪方法医学影像

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