Micro-CT of rodents: State-of-the-art and future perspectives

• We focus on preclinical micro-CT imaging, reviewing relevant principles, technologies, and applications.
• The primary limitations of micro-CT imaging are the associated radiation dose and relatively poor soft tissue contrast.
• High image quality is achievable with low radiation dose given ever more powerful reconstruction algorithms.
• Spectral micro-CT with passive or actively targeted nanoparticles will allow functional and molecular imaging.
• Phase contrast mechanisms will improve contrast relative to standard absorption micro-CT imaging.

Micron-scale computed tomography (micro-CT) is an essential tool for phenotyping and for elucidating diseases and their therapies. This work is focused on preclinical micro-CT imaging, reviewing relevant principles, technologies, and applications. Commonly, micro-CT provides high-resolution anatomic information, either on its own or in conjunction with lower-resolution functional imaging modalities such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT). More recently, however, advanced applications of micro-CT produce functional information by translating clinical applications to model systems (e.g. measuring cardiac functional metrics) and by pioneering new ones (e.g. measuring tumor vascular permeability with nanoparticle contrast agents). The primary limitations of micro-CT imaging are the associated radiation dose and relatively poor soft tissue contrast. We review several image reconstruction strategies based on iterative, statistical, and gradient sparsity regularization, demonstrating that high image quality is achievable with low radiation dose given ever more powerful computational resources. We also review two contrast mechanisms under intense development. The first is spectral contrast for quantitative material discrimination in combination with passive or actively targeted nanoparticle contrast agents. The second is phase contrast which measures refraction in biological tissues for improved contrast and potentially reduced radiation dose relative to standard absorption imaging. These technological advancements promise to develop micro-CT into a commonplace, functional and even molecular imaging modality.

The availability of micro-computed tomography (micro-CT) imaging has increased over the last decade and has shown its utility in many preclinical applications. The micro-CT instruments (Fig. 1) have evolved from custom-made to commercially available scanners designed for either ex vivo or in vivo imaging. We present fundamental principles, relevant technologies, and established applications before introducing new developments associated with spectral and phase contrast imaging. Micron-scale micro-CT is now an essential tool for phenotyping and for elucidating diseases and their therapies. These new technological advancements promise to further develop micro-CT into a commonplace, functional and even molecular imaging modality.Figure optionsDownload high-quality image (119 K)Download as PowerPoint slide