Department of Neurology, Wayne State University School of Medicine, Detroit, Michigan.
John D. Dingell VA Medical Center, Detroit, Michigan.
J Peripher Nerv Syst. 2019 Mar;24(1):87-93. doi: 10.1111/jns.12293. Epub 2018 Dec 11.
Irrespective of initial causes of neurological diseases, these disorders usually exhibit two key pathological changes-axonal loss or demyelination or a mixture of the two. Therefore, vigorous quantification of myelin and axons is essential in studying these diseases. However, the process of quantification has been labor intensive and time-consuming because of the requisite manual segmentation of myelin and axons from microscopic nerve images. As a part of AI development, deep learning has been utilized to automate certain tasks, such as image analysis. This study describes the development of a convolutional neural network (CNN)-based approach to segment images of mouse nerve cross sections. We adapted the U-Net architecture and used manually-produced segmentation data accumulated over many years in our lab for training. These images ranged from normal nerves to those afflicted by severe myelin and axon pathologies; thus, maximizing the trained model's ability to recognize atypical myelin structures. Morphometric data produced by applying the trained model to additional images were then compared to manually obtained morphometrics. The former effectively shortened the time consumption in the morphometric analysis with excellent accuracy in axonal density and g-ratio. However, we were not able to completely eliminate manual refinement of the segmentation product. We also observed small variations in axon diameter and myelin thickness within 9.5%. Nevertheless, we learned alternative ways to improve accuracy through the study. Overall, greatly increased efficiency in the CNN-based approach out-weighs minor limitations that will be addressed in future studies, thus justifying our confidence in its prospects. Note: All the relevant code is freely available at https://neurology.med.wayne.edu/drli-datashairing.
无论神经疾病的初始原因如何,这些疾病通常表现出两种关键的病理变化——轴突损失或脱髓鞘,或两者的混合。因此,在研究这些疾病时,强烈需要对髓鞘和轴突进行有力的量化。然而,由于必须从微观神经图像中手动分割髓鞘和轴突,因此量化过程既费力又耗时。作为人工智能开发的一部分,深度学习已被用于自动化某些任务,例如图像分析。本研究描述了一种基于卷积神经网络(CNN)的方法,用于分割小鼠神经切片的图像。我们改编了 U-Net 架构,并使用我们实验室多年来积累的手动制作的分割数据进行训练。这些图像范围从正常神经到严重的髓鞘和轴突病变的神经;因此,最大限度地提高了训练模型识别非典型髓鞘结构的能力。然后将应用训练模型获得的形态计量数据与手动获得的形态计量数据进行比较。前者通过出色的轴突密度和 g-ratio 准确性有效地缩短了形态计量分析的时间消耗。然而,我们无法完全消除分割产物的手动细化。我们还观察到 9.5%内的轴突直径和髓鞘厚度的微小变化。尽管如此,我们通过研究学习了提高准确性的替代方法。总体而言,基于 CNN 的方法的效率大大提高,克服了未来研究中需要解决的次要限制,因此我们对其前景充满信心。注:所有相关代码都可在 https://neurology.med.wayne.edu/drli-datashairing 免费获得。