Zhou Kevin C, Qian Ruobing, Degan Simone, Farsiu Sina, Izatt Joseph A
Department of Biomedical Engineering, Duke University, Durham, NC 27708.
Department of Radiology, Duke University Medical Center, Durham, NC 27708.
Nat Photonics. 2019 Nov;13(11):794-802. doi: 10.1038/s41566-019-0508-1. Epub 2019 Aug 19.
Optical coherence tomography (OCT) is a cross-sectional, micron-scale imaging modality with widespread clinical application. Typical OCT systems sacrifice lateral resolution to achieve long depths of focus for bulk tissue imaging, and hence tend to have better axial than lateral resolution. Such anisotropic resolution can obscure fine ultrastructural features. Furthermore, conventional OCT suffers from refraction-induced image distortions. Here, we introduce optical coherence refraction tomography (OCRT), which extends the superior axial resolution to the lateral dimension, synthesising undistorted cross-sectional image reconstructions from multiple conventional images acquired with angular diversity. In correcting refraction-induced distortions to register the OCT images, OCRT also achieves spatially resolved refractive index imaging. We demonstrate >3-fold improvement in lateral resolution as well as speckle reduction in imaging tissue ultrastructure, consistent with histology. With further optimisation in optical designs to incorporate angular diversity into clinical instruments, OCRT could be widely applied as an enhancement over conventional OCT.
光学相干断层扫描（OCT）是一种具有广泛临床应用的横断面微米级成像模态。典型的OCT系统为了实现对大块组织成像的长焦深而牺牲横向分辨率，因此轴向分辨率往往优于横向分辨率。这种各向异性分辨率会掩盖精细的超微结构特征。此外，传统OCT还存在折射引起的图像失真问题。在此，我们引入了光学相干折射断层扫描（OCRT），它将卓越的轴向分辨率扩展到横向维度，通过从以角度多样性采集的多个传统图像中合成无失真的横断面图像重建。在纠正折射引起的失真以配准OCT图像时，OCRT还实现了空间分辨的折射率成像。我们展示了在成像组织超微结构时横向分辨率提高了3倍以上以及散斑减少，与组织学结果一致。随着光学设计的进一步优化，将角度多样性纳入临床仪器，OCRT可作为传统OCT的增强技术得到广泛应用。
