| X-ray phase-contrast imaging (PCI) is a new imaging technique that provides high contrast and high resolution of biological soft tissues. Compared with the conventional x-ray imaging techniques, PCI is based on the principle that the x-ray phase-shift differences are far more sensitive than the absorption differences for imaging. For biological soft tissue, PCI has approximately1000times greater sensitivity than conventional radiography in the detection of minute density changes. Therefore, PCI can fulfil the conditions of micro imaging for biological soft tissue, and can reveal soft tissues discrimination at micrometer-scale resolution. This technique has also been introduced into x-ray computed tomography (PCI-CT). Combining the three dimensional (3D) visualization technique, PCI-CT can acquire3D morphology of inner microstructures in biomedical samples without contrast agents. In this paper, PCI was used to acquire the high-resolution micro-CT images of hepatic fibrosis (HF) and cavernous hemangioma of the liver (CHL). The research is to demonstrate the possibility of implementation of the PCI in a clinical environment, which will provide access to a practical, clinical diagnosis for HF and CHL.In this study, we first obtain the CT images of HF in Rats and CHL in human using diffraction enhanced imaging (DEI) and in-line phase-contrast imaging (ILPCI). Then, the3D micro structures of the samples were reconstructed. Finally, we researched the microvessels of HF and the microstructures of CHL by combining the histological sections. The main research contents are as follows:(1) DEI-CT were utilized to perform the investigation of HF in Rats. The experiments were performed at Beijing synchrotron radiation facility (BSRF) and Photon Factory (PF, KEK, Japan). Firstly, planar x-ray images using DEI and conventional radiograph were compared. The results reveal that DEI presents a higher spatial resolution and a higher contrast resolution than conventional radiography. Secondly, we compared the CT image with the pathological section image of the same specimen. The results show that the CT image has a close resemblance to the optical image of the stained histological section. Finally, combined with the3D visualization technique, DEI-CT enabled the acquisition of an accurate description of the3D vessel morphology from different stages of hepatic fibrosis. The research demonstrates that DEI-CT may allow morphologic descriptions and quantitative evaluation of vessel microstructures from different stages of hepatic fibrosis and can better characterize the various stages of fibrosis progression using high-resolution3D vessel morphology.(2) ILPCI-CT were utilized to perform the investigation of the sinusoid in human cavernous hemangioma of the liver (CHL). The experiments were performed at x-ray imaging and biomedical application beamline (BL13W1) of Shanghai Synchrotron Radiation Facility (SSRF) in China. Firstly, three stages of CHL samples images were acquired, and the accurate description of the3D microstructures are provided. Secondly, we compared the CT image and the pathological image of the same specimen. ILPCI-CT image shows a resemblance to optical image of stained histological section, which confirms the correspondence of the CT finding with the morphology of the samples. Finally, twenty single hepatic sinusoids were randomly chosen and visualized from3D visualization of CHL. The valuable morphological parameters of hepatic sinusoids, such as thrombi, diameters, surface areas and volumes, were measured. The results indicate that ILPCI-CT can acquire the abnormal and dilated hepatic sinusoids of CHL and the CT image has a close resemblance to the optical image of the stained histological section. Moreover, the greater degree of lesion, the severer dilation of hepatic sinusoids, and the greater of the diameter, surface area and volume of hepatic sinusoids. Thus, ILPCI-CT provides a new method for the research of microstructures in CHL. |
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