From Corrosion Casting to Virtual Dissection: Contrast-Enhanced Vascular Imaging using Hafnium Oxide Nanocrystals

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Nanotechnology

Background:

• Vascular corrosion casting provides 3D visualization of blood vessels but often damages fragile casts during tissue removal.
• Existing methods lack sufficient contrast for clear imaging of polymer casts within surrounding soft tissues.

Purpose of the Study:

• To develop a non-corrosive method for high-resolution 3D vascular casting using micro-CT.
• To enhance CT contrast of vascular casts using nanoparticle contrast agents.

Main Methods:

• In situ micro computed tomography (micro-CT) scans were employed, avoiding traditional tissue corrosion.
• Hafnium oxide nanocrystals (HfO2 NCs) were incorporated into the casting resin as CT contrast agents.
• Surface chemistry of HfO2 NCs was optimized for colloidal stability in the resin.

Main Results:

• The addition of HfO2 NCs significantly improved CT contrast, enabling straightforward segmentation of vascular casts.
• High-quality cardiovascular casts of zebrafish and mice were achieved with automatic segmentation using CT imaging software.
• Micro-scale details ($\mathrm{micro}$ m) were clearly differentiated without modifying resin injection techniques.

Conclusions:

• The proposed method enables virtual dissection of vascular casts in situ via contrast-enhanced CT imaging.
• This technique expands the application potential of vascular casting by preserving cast integrity and improving imaging resolution.
• Non-corrosive, contrast-enhanced micro-CT offers a powerful tool for detailed vascular anatomy studies.