An Ultralong-Circulating Tantalum-Based Computed Tomography Contrast Agent for Vascular Imaging in Large Animals

Area of Science:

• Biomedical Imaging
• Nanotechnology
• Radiology

Background:

• Current computed tomography angiography (CTA) contrast agents have limitations in real-time, long-term, and high-resolution vascular imaging.
• There is a need for advanced contrast agents to improve the diagnosis and prognostic evaluation of cardiovascular diseases.

Purpose of the Study:

• To develop an ultra-long-term CTA method using PEGylated ultrasmall tantalum oxide nanoparticles (Ta2O5-PEG NPs).
• To evaluate the efficacy of Ta2O5-PEG NPs for accurate imaging of cardiovascular diseases based on nanoparticle blood clearance.

Main Methods:

• Synthesis and characterization of PEGylated ultrasmall tantalum oxide nanoparticles (Ta2O5-PEG NPs).
• Evaluation of nanoparticle properties including water solubility, X-ray attenuation, biocompatibility, and hydrodynamic size.
• In vivo studies in rat, rabbit, and porcine models to assess blood circulation, imaging window, and diagnostic accuracy.

Main Results:

• Ta2O5-PEG NPs demonstrated exceptional water solubility (800 mg mL-1), strong X-ray attenuation, and good biocompatibility.
• The nanoparticles exhibited prolonged blood circulation (half-lives of ~19.8 h in rats, ~18.2 h in rabbits) and an extended imaging window up to 10 hours.
• High-resolution, whole-body vascular visualization was achieved, enabling accurate diagnosis and postoperative evaluation of vascular stenosis and thrombosis.

Conclusions:

• The proposed ultra-long-term CTA strategy using Ta2O5-PEG NPs offers a precise imaging approach for vascular diseases.
• This non-iodinated, high atomic number contrast agent has significant clinical translation potential for pre- and post-treatment evaluation of vascular conditions.