Polarization-sensitive optical projection tomography for muscle fiber imaging.

Mengjie Fang,Hui Hui,Jie Tian,Di Dong,Alicia Arranz,Chaoting Zeng,Xiao Liang,Xin Yang,Jorge Ripoll

doi:10.1038/srep19241

Abstract

Optical projection tomography (OPT) is a tool used for three-dimensional imaging of millimeter-scale biological samples, with the advantage of exhibiting isotropic resolution typically in the micron range. OPT can be divided into two types: transmission OPT (tOPT) and emission OPT (eOPT). Compared with eOPT, tOPT discriminates different tissues based on their absorption coefficient, either intrinsic or after specific staining. However, it fails to distinguish muscle fibers whose absorption coefficients are similar to surrounding tissues. To circumvent this problem, in this article we demonstrate a polarization sensitive OPT system which improves the detection and 3D imaging of muscle fibers by using polarized light. We also developed image acquisition and processing protocols that, together with the system, enable the clear visualization of muscles. Experimental results show that the muscle fibers of diaphragm and stomach, difficult to be distinguished in regular tOPT, were clearly displayed in our system, proving its potential use. Moreover, polarization sensitive OPT was fused with tOPT to investigate the stomach tissue comprehensively. Future applications of polarization sensitive OPT could be imaging other fiber-like structures such as myocardium or other tissues presenting high optical anisotropy.

Highlights

Detecting special optical properties such as birefringence[17]
In order to test possibility of measuring the birefringence properties of tissue with polarized light, we first show a result of mouse diaphragm from a commercial microscope to check whether the muscle fibers after clearing could be observed by polarized light
A polarization-sensitive Optical Projection Tomography (OPT) system with image acquisition and processing protocol was developed to enhance the detection of muscle fibers in a thin diaphragm section and inside the thick gastric wall were observed with polarization-sensitive Optical projection tomography (OPT)

Summary

Introduction

Detecting special optical properties such as birefringence[17]. In addition, polarized light imaging with mechanical sectioning allowed investigating deep fiber structures, with the drawback that the tomographic imaging is invasive and destructive[18]. Up to date polarization-sensitive OPT has not been used to observe biological specimens presenting optical anisotropy, such as muscle fibers. A mesoscopic imaging method for 3D imaging of anisotropic tissues is still in great demand. To circumvent this problem, in this article we propose a polarization-sensitive OPT system together with an image acquisition protocol and an image reconstruction and processing scheme for muscle fiber imaging. In contrast with current OPT methods, polarization-sensitive OPT may differentiate anisotropic tissues such as muscle fibers based on their birefringence properties. We describe the use of polarized light on transparent muscle fiber imaging and our system, presenting the image acquisition protocol as well as the image reconstruction and processing schemes before presenting our concluding remarks

Methods

Results

Conclusion