用证据学习提升CT重建精度,自动评估不确定性和修正误差。
ELECTRIC: Evidential Learning-Enhanced CT Reconstruction via Iterative Correction

- 基于贝叶斯框架构建迭代修正闭环,融合物理模型与神经网络
- 相比滤波反投影,重建误差降低70%,且不确定性可预测真实误差
- 适合低剂量CT重建场景,对先验强度不敏感,鲁棒性强
本文提出ELECTRIC(基于证据学习的迭代校正CT重建),一种物理引导的贝叶斯重建方法。通过证据神经网络提供图像初值与误差预测的主观不确定性代理,后者转化为自适应精度场,并嵌入泊松加权的最大后验更新中。由此形成图像-证据-精度-重建的闭环,将先验置信度作为迭代重建中的可学习状态变量。在AAPM梅奥诊所低剂量CT数据集的两组仿真研究中,使用透明代理估计器验证机制有效性,另一项可行性研究则采用训练好的正态逆伽马证据网络驱动完整闭环。在独立测试患者上,学习得到的先验均值使重建误差相对滤波反投影降低约70%;学习到的主观不确定性具有误差预测能力,支持选择性信任;物理引导的更新保证了测量一致性,自适应精度重建性能优于调优后的固定先验,且对先验强度误设表现出显著更强的鲁棒性。结果充分验证了ELECTRIC闭环流程的可行性,指出形式化不确定性校准与联合训练是未来主要方向。
原文摘要 · Abstract (English)
Here we introduce ELECTRIC (Evidential Learning-Enhanced CT Reconstruction via Iterative Correction), a physics-guided Bayesian formulation. An evidential neural network provides an image proposal and an error-predictive epistemic-uncertainty surrogate. The latter is converted into an adaptive precision field and inserted into a Poisson-weighted MAP update. The resulting image-evidence-precision-reconstruction loop treats prior confidence as a learned state variable of iterative reconstruction. In addition to the formulation and theoretical analysis, we report two simulation studies on image slices from the AAPM Mayo Clinic Low-Dose CT dataset: a mechanism-validation pilot using transparent surrogate estimators, and a feasibility study in which a trained Normal-Inverse-Gamma evidential network drives the full closed loop. On held-out patients, the learned prior mean reduces reconstruction error by roughly 70 percent relative to filtered back-projection, the learned epistemic uncertainty is error-predictive and supports selective trust, and the physics-guided update restores measurement consistency while the adaptive-precision reconstruction matches or exceeds a validation-tuned fixed prior and remains markedly more robust to prior-strength misspecification. Together these results demonstrate the complete ELECTRIC closed-loop pipeline, while identifying formal uncertainty calibration and joint training as the principal directions for future work.
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