用变分自编码器生成磁共振波谱数据,提升小样本场景下的信号质量。
Data-driven Synthesis of Magnetic Resonance Spectroscopy Data using a Variational Autoencoder
- 基于真实单体素波谱数据训练变分自编码器,学习低维复数谱表示。
- 生成数据能准确还原主要谱峰模式,提升信噪比与线宽表现。
- 适合需要数据增强的波谱分析任务,尤其关注信号质量改进者。
磁共振波谱(MRS)的深度学习发展常受限于高质量训练数据的稀缺。尽管物理模拟可缓解此问题,但难以精确建模所有体内信号成分。本文提出一种纯数据驱动的框架,使用变分自编码器(VAE)仅基于实测单体素波谱数据合成体内MRS数据。该模型学习复数谱的低维隐空间表示,并通过隐空间采样与插值生成新样本。通过重建质量、低维嵌入特征相似性、应用导向的信号质量指标及代谢物定量一致性等多维度评估,结果表明:该VAE能准确重构主要谱图模式,生成的数据占据与真实数据相同的特征空间。在针对GABA编辑波谱的应用中,用合成数据扩充有限瞬态数据集后,信噪比、半高全宽和形状评分均显著提升。然而,生成数据仍存在随机噪声建模不足、绝对代谢物定量精度下降等问题,尤其在浓度敏感应用中表现更明显。研究同时提出一套结构化评估框架,强调合成数据用于下游分析时需进行应用导向验证。
原文摘要 · Abstract (English)
The development of deep learning methods for magnetic resonance spectroscopy (MRS) is often hindered by limited availability of large, high-quality training datasets. While physics-based simulations are commonly used to mitigate this limitation, accurately modeling all in-vivo signal components remains challenging. In this work, we propose a data-driven framework for synthesizing in-vivo MRS data using a variational autoencoder (VAE) trained exclusively on measured single-voxel spectroscopy data. The model learns a low-dimensional latent representation of complex-valued spectra and enables generation of new samples through latent-space sampling and interpolation. The generative performance of the proposed approach is evaluated using a comprehensive set of complementary analyses, including reconstruction quality, feature-level similarity using low-dimensional embeddings, application-based signal quality metrics, and metabolite quantification agreement. The results demonstrate that the VAE accurately reconstructs dominant spectral patterns and generates synthetic spectra that occupy the same feature space as in-vivo data. In an example application targeting GABA-edited spectroscopy, augmenting limited subsets of transients with synthetic spectra improves signal quality metrics such as signal-to-noise ratio, linewidth, and shape scores. However, the results also reveal limitations of the generative approach, including under-representation of stochastic noise and reduced accuracy in absolute metabolite quantification, particularly for applications sensitive to concentration estimates. These findings highlight both potential and limitations of data-driven MRS synthesis. Beyond the proposed model, this study introduces a structured evaluation framework for generative MRS methods, emphasizing the importance of application-aware validation when synthetic data are used for downstream analysis.
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