Revealing Detailed Cartilage Function Through Nanoparticle Diffusion Imaging: A Computed Tomography & Finite Element...

Area of Science:

• Biomedical Engineering
• Orthopedics
• Medical Imaging

Background:

• Articular cartilage withstands mechanical stress via its unique structure.
• Accurate biomechanical models are crucial for understanding cartilage function but are limited by complex tissue analysis.
• Constituent-specific analysis is needed to improve cartilage modeling.

Purpose of the Study:

• To develop and validate a novel nanoparticle contrast-enhanced computed tomography (CECT) method for predicting constituent-specific biomechanical properties of articular cartilage.
• To assess the capability of CECT in evaluating fibrillar and non-fibrillar cartilage functionality and fluid flow.
• To demonstrate the feasibility of integrating CECT-derived properties into subject-specific biomechanical models.

Main Methods:

• Equine stifle joint cartilage samples (n=60) were imaged using micro-computed tomography (µCECT) with nanoparticle contrast agents.
• Two µCECT techniques were evaluated: conventional energy-integrating µCECT with cationic tantalum oxide nanoparticles (Ta2O5-cNP) and novel photon-counting µCECT with a dual-contrast agent (Ta2O5-cNP and iodixanol).
• Contrast agent uptake was correlated with cartilage functional properties derived from a fibril-reinforced poroelastic finite element model.

Main Results:

• The CECT method successfully predicted individual constituent-specific biomechanical properties of articular cartilage.
• The imaging techniques demonstrated the capacity to evaluate fibrillar and non-fibrillar cartilage functionality.
• Assessment of permeability-affected fluid flow within the cartilage was feasible using this method.

Conclusions:

• Novel nanoparticle CECT provides a method to determine constituent-specific biomechanical properties of articular cartilage.
• This technique enables the evaluation of cartilage fibrillar/non-fibrillar functionality and fluid dynamics.
• Incorporating these properties into biomechanical models offers potential for personalized cartilage diagnostics and treatment strategies.