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arXiv 2604.00985cs.CV

从预期扩散加权成像最大化T2-only前列腺癌定位

Maximizing T2-Only Prostate Cancer Localization from Expected Diffusion Weighted Imaging

UCL Hawkes Institute and the Department of Medical Physics and Biomedical Engineering, University College London(伦敦大学学院霍克斯研究所与医学物理与生物医学工程系);Centre for Bioengineering, School of Engineering and Materials Science and Digital Environment Research Institute, Queen Mary University of London(伦敦玛丽女王大学工程与材料科学学院生物工程中心与数字环境研究所);Centre for Medical Imaging, University College London(伦敦大学学院医学影像中心);Division of Surgery & Interventional Science, University College London(伦敦大学学院外科与介入科学部);Urological Research Network(泌尿研究网络)
Weixi Yi, Yipei Wang, Wen Yan, Hanyuan Zhang, Natasha Thorley, Alexander Ng, Shonit Punwani, Fernando Bianco, Mark Emberton, Veeru Kasivisvanathan, Dean C. Barr… 展开作者

Weixi Yi, Yipei Wang, Wen Yan, Hanyuan Zhang, Natasha Thorley, Alexander Ng, Shonit Punwani, Fernando Bianco, Mark Emberton, Veeru Kasivisvanathan, Dean C. Barratt, Shaheer U. Saeed, Yipeng Hu

AI总结:

本文提出利用T2加权图像和生成模型进行前列腺癌定位,通过期望最大化算法提升定位性能,相比传统方法在患者和区域层面表现更优。

摘要:

多参数MRI被推荐作为前列腺癌检测和定位的首选非侵入性方法,需要至少扩散加权(DWI)和T2加权(T2w)MRI序列。早期仅使用T2w图像的机器学习方法在分割放射科标注的病变方面表现出色。单模态T2-only方法通过减少获取其他序列的成本和专业知识,提供了显著的临床益处。本文研究了仅使用T2w图像进行推断的更具挑战性的应用,但旨在基于独立的组织病理学标签定位个体癌症。我们把DWI图像作为潜在模态(训练期间 readily available)来分类癌症存在情况,给定仅T2w图像作为输入。在得到的期望最大化算法中,潜在模态生成器(使用基于流匹配的生成模型实现)在E步骤中近似了潜在DWI图像后分布,而在M步骤中,癌症定位器同时与生成模型优化,以最大化癌症存在的期望似然。所提出的方法为从特权DWI模态学习提供了新的理论框架,相比缺乏训练DWI图像或现有特权学习和不完整模态框架的方法,实现了更优的癌症定位性能。所提出的T2-only方法在多个输入序列的基线方法上表现竞争或更优(例如,患者层面F1分数提高14.4%,区域层面QWK提高5.3%)。我们使用来自4133例前列腺癌患者内部和外部数据集进行定量评估,这些数据集具有组织病理学验证的标签。

英文摘要:

Multiparametric MRI is increasingly recommended as a first-line noninvasive approach to detect and localize prostate cancer, requiring at minimum diffusion-weighted (DWI) and T2-weighted (T2w) MR sequences. Early machine learning attempts using only T2w images have shown promising diagnostic performance in segmenting radiologist-annotated lesions. Such uni-modal T2-only approaches deliver substantial clinical benefits by reducing costs and expertise required to acquire other sequences. This work investigates an arguably more challenging application using only T2w at inference, but to localize individual cancers based on independent histopathology labels. We formulate DWI images as a latent modality (readily available during training) to classify cancer presence at local Barzell zones, given only T2w images as input. In the resulting expectation-maximization algorithm, a latent modality generator (implemented using a flow matching-based generative model) approximates the latent DWI image posterior distribution in the E-steps, while in M-steps a cancer localizer is simultaneously optimized with the generative model to maximize the expected likelihood of cancer presence. The proposed approach provides a novel theoretical framework for learning from a privileged DWI modality, yielding superior cancer localization performance compared to approaches that lack training DWI images or existing frameworks for privileged learning and incomplete modalities. The proposed T2-only methods perform competitively or better than baseline methods using multiple input sequences (e.g., improving the patient-level F1 score by 14.4\% and zone-level QWK by 5.3\% over the T2w+DWI baseline). We present quantitative evaluations using internal and external datasets from 4,133 prostate cancer patients with histopathology-verified labels.

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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