Abstract
Summary Statement
In this study, we employed a novel imaging modalities, the synchrotron radiation microcomputed tomography (SRμCT) to visualise the 3D morphology of the spinal cord microvasculature and successfully obtained the 3D images.
Introduction
Understanding the morphology of the spinal cord microvasculature in three-dimensions (3D) is limited by the lack of an effective high-resolution imaging technique. In this study, we used two novel imaging modalities, conventional x-ray microcomputed tomography (CμCT) and synchrotron radiation microcomputed tomography (SRμCT), to visualise the 3D morphology of the spinal cord microvasculature and to compare their utility in basic science research.
Methods
(1) Sample Preparation: Ten adult Sprague-Dawley male rats (250–300 g) were randomly divided into A and B groups (n = 5). Both groups were subjected to angiography with contrast agent (Microfil MV-122, Flow Tech, CA, USA). The samples in group A were examined by CμCT, and the group B samples were analyzed through SRμCT scanning. After scanning, the samples was photographed with a stereomicroscope. (2) Images Analysis: The morphometric parameters in 2D were calculated using the Image-Pro Plus program (Ver. 6.0, Media Cybernetics. Bethesda, MD, USA), In the 3D dataset, the algorithms for the analysis of vessel structures in the VG Studio Max software package (Volume Graphics GmbH, Germany) were applied to calculate the morphological parameters of the spinal cord microvasculature.
Results
The reconstructed tomographic slices of the rat spinal cord microvasculature obtained by these two techniques are illustrated. In the 2D tomographic view, the area with a high gray value, which indicates the location of the vessels, could be easily differentiated from the neural parenchymal background. The CμCT slices dataset only provided indistinctive images with weak apparent artefacts. In contrast, extensive distributions of the microvessels were found in the intrinsic neural parenchyma in the SRμCT slices. (2) The 3D reconstructed image obtained through SRμCT, provided a clear and precise configuration of the complex spatial structure and connectivity of the intensive microvasculature of the spinal cord when compared with CμCT. (3) The extracted 3D spatial distribution image of the spinal cord microvasculature was able to match the specimen's morphology photographed with a stereomicroscope.
Discussion & Conclusion
In this study, we have combined two emerging techniques to capture the 3D morphological features of the rat spinal cord microvasculature in vitro for the first time. With the help of contrast agents and the advanced computed tomography algorithm, both CμCT and SRμCT were able to provide a valuable 3D volumetric dataset of the spinal cord vascular structure. These datasets could be extracted and analyzed from different angles and at multiple levels, which are analysis that were not previously possible with the conventional histological methods. However, when compared with CμCT, SRμCT was able to achieve higher-resolution vascular imaging and to obtain detailed 3D morphological features of the spinal cord microvasculature. These data imply that SRμCT may be regarded as a unique imaging technique that is more suitable than CμCT for 3D angioarchitectural investigation in preclinical neurovascular research.
