Advances in micro-CT imaging of small animals

Abstract

Micron-scale computed tomography (micro-CT) imaging is a ubiquitous, cost-effective, and non-invasive three-dimensional imaging modality. We review recent developments and applications of micro-CT for preclinical research. Methods: Based on a comprehensive review of recent micro-CT literature, we summarize features of state-of-theart hardware and ongoing challenges and promising research directions in the field. Results: Representative features of commercially available micro-CT scanners and some new applications for both in vivo and ex vivo imaging are described. New advancements include spectral scanning using dual-energy micro-CT based on energy-integrating detectors or a new generation of photon-counting x-ray detectors (PCDs). Beyond two-material discrimination, PCDs enable quantitative differentiation of intrinsic tissues from one or more extrinsic contrast agents. When these extrinsic contrast agents are incorporated into a nanoparticle platform (e.g. liposomes), novel micro-CT imaging applications are possible such as combined therapy and diagnostic imaging in the field of cancer theranostics. Another major area of research in micro-CT is in x-ray phase contrast (XPC) imaging. XPC imaging opens CT to many new imaging applications because phase changes are more sensitive to density variations in soft tissues than standard absorption imaging. We further review the impact of deep learning on micro-CT. We feature several recent works which have successfully applied deep learning to micro-CT data, and we outline several challenges specific to micro-CT. Conclusions: All of these advancements establish micro-CT imaging at the forefront of preclinical research, able to provide anatomical, functional, and even molecular information while serving as a testbench for translational research.

A scoping review of small animal image-guided radiotherapy research: Advances, impact and future opportunities in translational radiobiology

“…Imaging is a common area of research across physics and biology contributions. Small animal irradiators are fitted with micro-CT or CBCT imaging platforms at a lower energy than used clinically [21] . Imaging focused studies within physics contributions (22%) mainly aim to improve the spatial resolution whilst maintaining a low imaging dose.…”

β-Ecdysterone Enhanced Bone Regeneration Through the BMP-2/SMAD/RUNX2/Osterix Signaling Pathway

“…All samples collected from rat models with femoral condylar defects were fixed in 4% paraformaldehyde at room temperature for 24 h. Micro-computed tomography (CT) (u-ct80, SCANCO, Switzerland) was used to test the samples ( Clark and Badea 2021 ). Three-dimensional reconstruction was performed using the processed images (Scanco ® software) and the bone volume, trabecular thickness, and bone mineral density of each group were detected and analyzed.…”

Imaging Regional Lung Structure and Function in Small Animals Using Synchrotron Radiation Phase-Contrast and K-Edge Subtraction Computed Tomography

“…A multitude of interesting methods and algorithms have been developed for conventional micro-CT of the lung, with prospective and retrospective gating, motion compensation, and radiation dose reduction via sophisticated reconstruction algorithms. These have been extensively reviewed previously ( Ashton et al, 2015 ; Clark and Badea, 2021 ). However, conventional CT is limited by the low radiation flux available in standard X-ray imaging systems, which reduces the spatial and temporal resolution, particularly in in vivo imaging.…”