PURPOSE The three-dimensional (3D) structure of the human nipple has not been fully clarified. However, its importance has increased in recent years because it has become common practice to preoperatively explore the spread of breast cancer to the nipple with needle biopsy, ductoscopy, and/or ductal lavage for nipple-sparing mastectomy. Here, we demonstrated that X-ray dark-field computed tomography (XDFI-CT) is a powerful tool for reconstructing the 3D distribution pattern of human lactiferous ducts non-destructively, without contrast agent, and with high tissue contrast. METHODS Nipples amputated from mastectomy specimens of 51 patients with breast cancer were visualized three-dimensionally by XDFI-CT. First, CT images and conventionally stained tissue sections were compared to demonstrate that XDFI-CT provides 3D anatomical information. Next, the number of ducts in the nipple and the number of ducts sharing an ostium near the tip of the nipple were measured from the volume set of XDFI-CT. Finally, the 3D distribution pattern of the ducts was determined. RESULTS XDFI-CT can provide images almost equivalent to those of low-magnification light microscopy of conventional hematoxylin-eosin-stained histological sections. The mean number of ducts in all cases was 28.0. The total number of ducts sharing an ostium near the tip of the nipple was 525 of 1428. The 3D distribution patterns of the ducts were classified into three types that we defined as convergent (22%), straight (39%), or divergent (39%). CONCLUSIONS XDFI-CT is useful for exploring the microanatomy of the human nipple and might be used for non-invasive nipple diagnosis in the future.

中文翻译：

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X射线暗场计算机断层扫描显像的人类乳头的三维显微解剖。

目的尚未完全阐明人乳头的三维（3D）结构。但是，近年来它的重要性提高了，因为通过针刺活检，导管镜检查和/或导管冲洗术进行保留乳头的乳房切除术已成为术前探索乳腺癌向乳头扩散的普遍做法。在这里，我们证明了X射线暗场计算机断层扫描（XDFI-CT）是一种强大的工具，可以无损地重建人类乳腺导管的3D分布模式，无需造影剂，并且具有较高的组织对比度。方法采用XDFI-CT技术对51例乳腺癌患者的乳房切除术标本切除的乳头进行三维可视化。首先，将CT图像和常规染色的组织切片进行比较，以证明XDFI-CT提供了3D解剖信息。下一个，根据XDFI-CT的体积测量，测量乳头中的导管数量和在乳头尖端附近共有一个口的导管数量。最后，确定管道的3D分布模式。结果XDFI-CT可提供的图像几乎与常规苏木精-伊红染色的组织切片的低倍光学显微镜图像相同。在所有情况下，平均导管数量为28.0。在乳头尖端附近共有一个口的导管总数为1428的525。导管的3D分布模式分为三种类型，我们定义为会聚（22％），笔直（39％）或发散（ 39％）。结论XDFI-CT可用于探索人类乳头的微观解剖结构，并且将来可能用于非侵入性乳头诊断。