Background and objectives

: The nucleus is a complex and dynamic organelle enclosing the major part of the cell's genome. A growing body of evidence suggests that changes in the shape of this organelle can influence cell activities. The other way around, altered nuclear shape may be indicative of impaired cell function. Symmetry is an important aspect of nuclear shape not receiving the attention it merits. We address this problem by presenting a software tool allowing to quantify nuclear shape asymmetry in light microscopy images.

Methods

: The software named nPAsym is written in Scala and implemented as a plugin to ImageJ making possible to use it in combination with other ImageJ tools. The plugin works with 8-bit images segmented into black nuclear masks and white background. It performs a number of operations allowing to analyze multiple objects within a single image, removing some segmentation artefacts, filtering out objects incomplete and below a specified size. The feature of interest is quantified using the notion of point asymmetry. The performance of nPAsym was tested in a small-scale study comparing nuclear shapes for cells of nodular goiter, follicular thyroid adenoma and papillary thyroid carcinoma.

Results

: We present nPAsym, the ImageJ plugin, that measures nuclear shape asymmetry. It works with digital microscopic images segmented using either a raster graphics editor or built-in ImageJ functions. nPAsym is packaged in a single .jar file and does not require installation as well as configuration. It has proved effective in distinguishing between some of the nuclear shape phenotypes.

Conclusions

: nPAsym is the user-friendly, platform-independent and open-source software tool allowing to quantify nuclear shape asymmetry in digital images captured from cytologic and histologic preparations. It has a potential to become useful for both experimental research and diagnostics.

中文翻译：

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nPAsym：ImageJ的开源插件，用于量化核形状不对称性。

背景和目标

：细胞核是一个复杂而动态的细胞器，包围着细胞基因组的主要部分。越来越多的证据表明，这种细胞器形状的改变会影响细胞的活动。相反，改变的核形状可能表明细胞功能受损。对称性是核形状的一个重要方面，没有得到应有的重视。我们通过提出一种软件工具来解决这个问题，该工具可以量化光学显微镜图像中的核形状不对称性。

方法

：名为nPAsym的软件是用Scala编写的，并作为ImageJ的插件实现，从而可以与其他ImageJ工具结合使用。该插件可将8位图像分割成黑色核遮罩和白色背景。它执行许多操作，可以分析单个图像中的多个对象，消除一些分割伪像，滤除不完整且小于指定大小的对象。使用点不对称性的概念来量化感兴趣的特征。在一项小规模研究中测试了nPAsym的性能，比较了结节性甲状腺肿，滤泡性甲状腺腺瘤和甲状腺乳头状癌的细胞核形状。

结果

：我们介绍了nPAsym，即ImageJ插件，用于测量核形状不对称性。它适用于使用光栅图形编辑器或内置ImageJ函数进行分割的数字显微图像。nPAsym打包在单个.jar文件中，不需要安装和配置。事实证明，它可以有效区分某些核形状表型。

结论

：nPAsym是用户友好，独立于平台的开源软件工具，可用于量化从细胞学和组织学制剂中捕获的数字图像中的核形状不对称性。它有可能在实验研究和诊断中变得有用。