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arXiv 2005.12573eess.IVcs.CV

学习正常脑解剖结构的全局与局部特征用于无监督异常检测

Learning Global and Local Features of Normal Brain Anatomy for Unsupervised Abnormality Detection

National Cancer Center Research Institute(国家癌症中心研究所);RIKEN Center for Advanced Intelligence Project(理化学研究所先进智能项目中心);Graduate School of Information Science and Technology, The University of Tokyo(东京大学信息科学与技术研究生院);Research Center for Advanced Science and Technology, The University of Tokyo(东京大学先进科学技术研究中心);National Cancer Center Hospital(国家癌症中心医院)

Kazuma Kobayashi, Ryuichiro Hataya, Yusuke Kurose, Amina Bolatkan, Mototaka Miyake, Hirokazu Watanabe, Masamichi Takahashi, Jun Itami, Tatsuya Harada, Ryuji Hamamoto

AI总结:

本研究提出一种无监督学习框架,通过训练仅使用正常脑部MRI的图像重建与判别网络,利用全局正常解剖特征与局部差异检测异常,还设计了解剖保真度指标,在多种脑部异常检测中取得了对应AUC结果。

摘要:

在现实临床实践中,漏诊意外发现可能导致严重后果。然而,作为当前深度学习成功基础的监督学习,仅促使模型识别数据集中预先定义的异常。因此,必须在不局限于特定疾病类别的医学图像中实现异常检测。本研究提出了一种无监督学习框架,用于在转移性脑肿瘤患者群体的脑部磁共振成像中进行像素级异常检测。我们的核心思路是:若图像重建网络能够忠实复现正常解剖结构的全局特征,那么未见过图像中的异常病灶可通过判别网络,将其与被重建为正常的图像进行局部差异比对来识别。两个网络均在仅包含无标签正常图像的数据集上训练。此外,我们设计了一种评估重建图像解剖保真度的指标,并证实当图像重建网络取得更高得分时,整体检测性能会提升。在评估阶段,我们对具有临床意义的异常进行了全面分割。结果显示,转移性脑肿瘤、颅外转移瘤、术后残腔和结构改变的受试者工作特征曲线下面积值分别为0.78、0.61、0.91和0.60。

英文摘要:

In real-world clinical practice, overlooking unanticipated findings can result in serious consequences. However, supervised learning, which is the foundation for the current success of deep learning, only encourages models to identify abnormalities that are defined in datasets in advance. Therefore, abnormality detection must be implemented in medical images that are not limited to a specific disease category. In this study, we demonstrate an unsupervised learning framework for pixel-wise abnormality detection in brain magnetic resonance imaging captured from a patient population with metastatic brain tumor. Our concept is as follows: If an image reconstruction network can faithfully reproduce the global features of normal anatomy, then the abnormal lesions in unseen images can be identified based on the local difference from those reconstructed as normal by a discriminative network. Both networks are trained on a dataset comprising only normal images without labels. In addition, we devise a metric to evaluate the anatomical fidelity of the reconstructed images and confirm that the overall detection performance is improved when the image reconstruction network achieves a higher score. For evaluation, clinically significant abnormalities are comprehensively segmented. The results show that the area under the receiver operating characteristics curve values for metastatic brain tumors, extracranial metastatic tumors, postoperative cavities, and structural changes are 0.78, 0.61, 0.91, and 0.60, respectively.

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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