arXiv:2603.17968cs.CV2026-03

提出Robust-ComBat,解决脑部MRI数据因病理性异常值导致的校正偏差问题。

Robust-ComBat: Mitigating Outlier Effects in Diffusion MRI Data Harmonization

  • 用简单MLP替代传统过滤,动态补偿异常值影响
  • 在含80%患者的数据中,校正误差显著低于传统方法
  • 适合临床真实场景中混有未诊断患者的多中心研究

ComBat等校正方法广泛用于缓解扩散MRI(dMRI)的站点偏差,但其假设受试者数据呈高斯分布。实际中,神经疾病患者扩散指标常显著偏离健康对照,产生病理异常值,干扰站点效应估计。尤其在临床实践中,多数接受脑成像的患者存在潜在未诊断疾病,难以排除出校正队列——恰恰是这些扫描用于确诊。本文发现,使用ComBat对包含病理病例的正常参考人群进行校正,会产生显著偏差。我们在7种神经疾病中评估了10种异常值剔除方法与4种ComBat变体,在多种情景下发现多数过滤策略在病理存在时失效。相比之下,一个简单的MLP能稳健补偿异常值,实现可靠校正并保留疾病信号。在包含最多80%神经疾病患者的真实多中心队列上,Robust-ComBat始终优于传统统计基线,所有ComBat变体的校正误差均更低。

原文摘要 · Abstract (English)

Harmonization methods such as ComBat and its variants are widely used to mitigate diffusion MRI (dMRI) site-specific biases. However, ComBat assumes that subject distributions exhibit a Gaussian profile. In practice, patients with neurological disorders often present diffusion metrics that deviate markedly from those of healthy controls, introducing pathological outliers that distort site-effect estimation. This problem is particularly challenging in clinical practice as most patients undergoing brain imaging have an underlying and yet undiagnosed condition, making it difficult to exclude them from harmonization cohorts, as their scans were precisely prescribed to establish a diagnosis. In this paper, we show that harmonizing data to a normative reference population with ComBat while including pathological cases induces significant distortions. Across 7 neurological conditions, we evaluated 10 outlier rejection methods with 4 ComBat variants over a wide range of scenarios, revealing that many filtering strategies fail in the presence of pathology. In contrast, a simple MLP provides robust outlier compensation enabling reliable harmonization while preserving disease-related signal. Experiments on both control and real multi-site cohorts, comprising up to 80% of subjects with neurological disorders, demonstrate that Robust-ComBat consistently outperforms conventional statistical baselines with lower harmonization error across all ComBat variants.

MRI校正异常值处理多中心研究扩散成像

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