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Updated: May 21, 2026
Micro-CT Imaging and Morphometric Analysis of Mouse Neonatal Brains
Published on: May 19, 2023
Ex vivo imaging of mouse brain using micro-CT with non-ionic iodinated contrast agent: a comparison with myelin
1Department of Medical Physics and Engineering, Division of Medical Technology and Science, Faculty of Health Science, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan. saito@sahs.med.osaka-u.ac.jp
Objective:
We investigated the use of micro-CT with contrast agent for the non-invasive characterisation of fixed mouse brain tissue specimens as a means to differentiate between grey and white matter.
Methods:
Nine mice were divided into two groups for micro-CT (n=6) and myelin staining (n=3) experiments. Six mice underwent in vivo micro-CT and were then prepared for brain specimens by transcardiac perfusion with paraformaldehyde. The six mouse brains were soaked in two different concentrations of non-ionic iodinated contrast agents (60 and 150 mg ml(-1)). Immersion times used for each concentration of iodine were for 3, 7 and 14 days. Three-dimensional ex vivo micro-CT images were acquired with a resolution of 39 μm(3) to create isotropic images. The other three mice were stained for evaluation of the myelin structure.
Results:
Soaking the brains in non-ionic iodinated contrast agent resulted in clear differences in signal between the grey matter, the white matter and the ventricular spaces. The 150 mg ml(-1) contrast agent solution yielded images with better contrast-to-noise ratio (CNR) than 60 mg ml(-1) iodine contrast agent solution. 14 days of soaking yielded images with better CNR than 3 and 7 days. The CT contrast of grey and white matter derived from the iodine-soaked fixed brains was strongly related to tissue myelin.
Conclusion:
The present study demonstrated that micro-CT can be used to detect the mouse brain myelin structure at 3, 7 and 14 days after fixation using a CT contrast agent.
Insights
Micro-computed tomography (micro-CT) with contrast agents can non-invasively differentiate mouse brain grey and white matter. This technique effectively visualizes myelin structure in fixed brain tissue specimens.
Area of Science:
- Neuroimaging
- Biomedical Engineering
- Histology
Background:
- Accurate characterization of brain tissue microstructure is crucial for understanding neurological function and disease.
- Traditional methods for differentiating grey and white matter often require invasive procedures or destructive staining.
- Non-invasive imaging techniques offer a promising alternative for analyzing fixed biological specimens.
Purpose of the Study:
- To investigate the efficacy of micro-computed tomography (micro-CT) combined with contrast agents for non-invasively distinguishing between grey and white matter in fixed mouse brain tissue.
- To assess the relationship between micro-CT contrast and myelin content in brain specimens.
Main Methods:
- Six mouse brains underwent in vivo micro-CT followed by fixation and ex vivo micro-CT imaging.
- Fixed brain specimens were immersed in non-ionic iodinated contrast agents at concentrations of 60 and 150 mg/mL for 3, 7, and 14 days.
- Three-dimensional micro-CT images were acquired at a resolution of 39 μm³; myelin staining was performed on three additional mice for comparison.
Main Results:
- Micro-CT imaging with iodinated contrast agents revealed distinct signal differences between grey matter, white matter, and ventricular spaces.
- Higher contrast-to-noise ratio (CNR) was achieved using 150 mg/mL contrast agent and 14 days of immersion time.
- The CT contrast observed in fixed, contrast-agent-soaked brains showed a strong correlation with the tissue's myelin content.
Conclusions:
- Micro-CT with CT contrast agents provides a viable non-invasive method for visualizing mouse brain myelin structure.
- This technique allows for the differentiation of grey and white matter in fixed brain tissue up to 14 days post-fixation.
