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arXiv 2610.13237eess.IVcs.CVcs.LG

医学影像中联合嵌入预测架构(JEPA)的可预测性偏差

The Predictability Bias of Joint-Embedding Predictive Learning in Medical Imaging

Technical University of Munich (TUM) and TUM University Hospital(慕尼黑工业大学和慕尼黑大学医院);Technical University of Munich, School of Medicine and Health, TUM University Hospital, Klinikum rechts der Isar, Department of Diagnostic and Interventional Radiology(慕尼黑大学医学院和健康学院,慕尼黑大学医院,伊萨尔河右岸诊所,诊断与介入放射学系);Friedrich-Alexander University Erlangen-Nürnberg(埃尔朗根-纽伦堡弗里德里希·阿列克桑德大学);Department of Computing, Imperial College London(伦敦帝国理工学院计算机系);Institute for Medical AI (IMAI), Heidelberg University Hospital and Medical Faculty of Heidelberg University(海德堡大学医院医学人工智能研究所和海德堡大学医学院);Else Kroener Fresenius Center for Digital Health (EKFZ), Faculty of Medicine Carl Gustav Carus, TUD Dresden University of Technology(德累斯顿工业大学卡尔·古斯塔夫·卡鲁斯医学院 Else Kroener Fresenius 数字健康中心);Munich Center for Machine Learning (MCML)(慕尼黑机器学习中心);Institute for Artificial Intelligence in Medicine (IKIM), University Hospital Essen (AöR)(埃森大学医院医学人工智能研究所);Institute of Interventional and Diagnostic Radiology and Neuroradiology, University Hospital Essen(埃森大学医院介入与诊断放射学及神经放射学研究所);National Center for Tumor Diseases West(西德国立肿瘤疾病中心)

Fabian Drexel, Bernhard Kainz, Jakob N. Kather, Daniel Rueckert, Lisa C. Adams, Keno K. Bressem, Cosmin I. Bercea

AI总结:

该研究针对医学影像中联合嵌入预测架构(JEPA)的可预测性偏差,提出TAP-JEPA模型,发现上下文可预测性不足以代表临床相关性,训练目标需保留诊断特征。

摘要:

联合嵌入预测架构(JEPAs)通过从可见上下文预测被掩码区域的教师表示进行学习。点预测汇总了条件目标分布,无法复现上下文未解析的变异,我们将这种约束称为可预测性偏差。在计算机断层扫描(CT)中,循环解剖结构可通过上下文预测,而决定临床解读的散发性、局灶性病理通常无法预测。我们引入TAP-JEPA,这是一种在113611个CT体积上训练的ViT-B/3D模型,在扫描级分类任务中与最先进的编码器(COLIPRI、Merlin、VoxelFM)具有竞争力。随后,我们通过复现训练期间使用的精确掩码、教师和预测器计算来审计学习到的预测通路。预测使病理的平均技能(患病率归一化平均精度)从0.388降至0.271,但仅使解剖结构的平均技能从0.921降至0.873。沿教师方向,将同一器官中病理与匹配的对照区域分离,预测使病理向对照区域移动34.7%,使对照区域向病理移动13.6%,且离可见上下文越远,移动幅度越大。在四类病理中,替换可见匹配对照表示比完全替换病理表示会增加更多的周围目标预测损失。下游任务中,移除所有最终层病理标记会在七个扫描级探针中的四个中使决策 margin 最多降低0.45%。这些结果共同表明,在医学表示学习中,上下文可预测性不是临床相关性的充分替代指标,因此训练目标应保留诊断特征,无论其能否从周围解剖结构预测。

英文摘要:

Joint-embedding predictive architectures (JEPAs) learn by predicting teacher representations of masked regions from visible context. Point prediction summarizes the conditional target distribution and cannot reproduce variation that the context does not resolve. We call this constraint predictability bias. In computed tomography (CT), recurrent anatomy is predictable from context, whereas the sporadic, localized pathology that determines clinical interpretation often is not. We introduce TAP-JEPA, a ViT-B/3D trained on 113,611 CT volumes that is competitive with state-of-the-art encoders (COLIPRI, Merlin, VoxelFM) in scan-level classification. We then audit the learned predictive pathway by replaying the exact masking, teacher, and predictor computations used during training. Prediction lowers the mean Skill (prevalence-normalized average precision) from 0.388 to 0.271 for pathology, but only from 0.921 to 0.873 for anatomy. Along the teacher direction, separating pathology from matched control regions in the same organ, prediction moves pathology 34.7% toward the controls and controls 13.6% toward pathology, with larger shifts farther from visible context. Replacing visible matched-control representations increases surrounding-target prediction loss more than fully replacing pathology representations across four pathology categories. Downstream, removing all final-layer pathology tokens reduces the decision margin by at most 0.45% in four of seven scan-level probes. Together, these results show that contextual predictability is not a sufficient proxy for clinical relevance in medical representation learning. Training objectives should therefore retain diagnostic features regardless of their predictability from surrounding anatomy.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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