Rapid and robust whole slide imaging based on LED-array illumination and color-multiplexed single-shot autofocusing
Rapid and robust whole slide imaging based on LED-array illumination and color-multiplexed single-shot autofocusing
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DOI：
10.21037/qims.2019.05.04
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发表时间：
2019-05-01
影响因子：
2.8
通讯作者：
Zheng, Guoan
中科院分区：
文献类型：
--
作者：
Jiang, Shaowei;Bian, Zichao;Zheng, Guoan
背景：在成像硬件的进步和机器学习的进步的推动下，数字病理学正在经历指数增长期。最近，美国已批准使用全切片成像 (WSI) 进行数字病理学初步诊断。在手术过程中使用冰冻切片程序快速识别癌组织的需求是 WSI 发展的另一个驱动力。传统的 WSI 系统将组织载玻片扫描到不同位置并获取数字图像。在典型的实施中，在扫描过程之前创建焦点图，这会导致大量的开销时间并且需要机械系统的高定位精度。 WSI 系统的最终成本对于手术期间的冰冻切片程序来说通常是令人望而却步的。方法：我们报告了一种基于用于样本照明的可编程 LED 阵列的新型 WSI 方案。在两次常规明场图像采集之间，我们通过打开红色和绿色 LED 进行彩色复用照明来获取另一幅图像。然后，我们通过最大化图像互信息或互相关来识别红色和绿色通道图像的平移。由此产生的平移位移用于扫描过程中的动态焦点校正。由于我们在相邻采集期间跟踪差异焦点，因此我们的方案中没有位置重复性要求。结果：我们演示了平均聚焦误差类似于 0.3 微米的原型 WSI 平台。与以前的实现不同，该原型平台不需要焦点图测量，不需要辅助相机或额外的光学器件，并且允许在焦点跟踪过程中连续样本运动。 结论：可编程 LED 阵列可用于 WSI 中的颜色复用单次自动对焦。所报告的方案可以实现具有成本效益的 WSI 平台的开发，而无需位置重复性要求。它还可以为其他高内涵显微镜应用提供交钥匙解决方案。
Background: Digital pathology is experiencing an exponential period of growth catalyzed by advancements in imaging hardware and progresses in machine learning. The use of whole slide imaging (WSI) for digital pathology has recently been cleared for primary diagnosis in the US. The demand for using frozen section procedure for rapid identification of cancerous tissue during surgery is another driving force for the development of WSI. A conventional WSI system scans the tissue slide to different positions and acquires the digital images. In a typical implementation, a focus map is created prior to the scanning process, leading to significant overhead time and a necessity for high positional accuracy of the mechanical system. The resulting cost of WSI system is often prohibitive for frozen section procedure during surgery.Methods: We report a novel WSI scheme based on a programmable LED array for sample illumination. In between two regular brightfield image acquisitions, we acquire one additional image by turning on a red and a green LED for color multiplexed illumination. We then identify the translational shift of the red- and green-channel images by maximizing the image mutual information or cross-correlation. The resulting translational shift is used for dynamic focus correction in the scanning process. Since we track the differential focus during adjacent acquisitions, there is no positional repeatability requirement in our scheme.Results: We demonstrate a prototype WSI platform with a mean focusing error of similar to 0.3 microns. Different from previous implementations, this prototype platform requires no focus map surveying, no secondary camera or additional optics, and allows for continuous sample motion in the focus tracking process.Conclusions: A programmable LED array can be used for color-multiplexed single-shot autofocusing in WSI. The reported scheme may enable the development of cost-effective WSI platforms without positional repeatability requirement. It may also provide a turnkey solution for other high-content microscopy applications.