RESEARCH

Three-dimensional imaging of biological microstructures

Important microstructural information exists inside biological tissues that cannot be captured by conventional observation methods. Fine morphological features of bone and soft tissues, subtle density differences, and intricate vascular networks all play essential roles in elucidating disease mechanisms, quantitatively evaluating therapeutic effects, and developing new diagnostic technologies.

Our laboratory focuses on biomedical imaging and image analysis for visualizing and quantifying microstructures in biological tissues, using micro-X-ray CT and optical coherence tomography (OCT) as core technologies.

By integrating the entire workflow, from imaging system design and acquisition optimization to image reconstruction and image analysis, we aim to develop images beyond simple visualization results into quantitative information for understanding biological tissues.

Micro-CT | Non-destructive three-dimensional morphological imaging

Micro-CT is an X-ray imaging technology that enables observation of internal three-dimensional microstructures without cutting the specimen. It can capture structures that are invisible to the naked eye in three dimensions and in a quantitative manner, including bone, blood vessels, soft tissues, pathological specimens, and small animals.

However, micro-CT imaging of biological tissues involves complex trade-offs among spatial resolution, contrast, radiation dose, and acquisition time. Increasing the spatial resolution generally requires a higher radiation dose and longer acquisition time, whereas reducing the dose increases noise and artifacts. In addition, because soft tissues have small differences in X-ray absorption, it is often difficult to clearly visualize their structures using conventional absorption-contrast CT.

Our laboratory studies micro-CT as an integrated measurement process, rather than treating the imaging system, acquisition conditions, image reconstruction, and image analysis as separate components. By linking hardware design, image reconstruction algorithms, and three-dimensional quantitative analysis, we aim to develop micro-CT technologies that can capture biological tissue structures with lower dose, higher accuracy, and greater reliability.

Ongoing research topics, publicly available information only

• Development of phase-contrast micro-X-ray CT systems
• Development of image reconstruction methods using sparse-view projection data
• Visualization of morphological variation in evolutionary biology and analysis of three-dimensional micro-CT data
• Development of low-dose micro-CT systems using pulsed X-ray sources

OCT | Optical imaging of tissue structures and vascular information

Optical coherence tomography (OCT) is an imaging technology that uses light to non-invasively observe cross-sectional structures of biological tissues. In ophthalmology, it is widely used for visualizing retinal and choroidal layer structures with high resolution, as well as for diagnosing diseases and evaluating therapeutic effects. OCT angiography (OCTA) further enables visualization of vascular structures without contrast agents, and is applied to the evaluation of vascular network changes and blood-flow-related information.

To stably extract information useful for diagnosis and research from OCT/OCTA images, highly accurate image analysis technologies are essential. Quantitative evaluation of tissue structures and vascular information is challenging because of unclear layer boundaries, noise, individual variability, and disease-related structural changes. Therefore, it is important not only to observe images, but also to extract such information numerically and connect it to disease understanding and treatment planning.

Our laboratory develops image analysis technologies for transforming structures captured in OCT/OCTA images into quantitative information. From three-dimensional tissue structure analysis and quantitative evaluation of vascular networks to AI-based automated analysis, we aim to build analytical platforms that can be used in clinical and research settings.

Ongoing research topics, publicly available information only

• Segmentation and quantitative analysis of three-dimensional choroidal structures using OCT images
• Quantitative analysis of tissue structures in OCT images of diseased eyes

If you are interested in collaborative research, please contact us through the Contact page.