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Published on: April 23, 2017
Bath Concentration of Anionic Contrast Agents Does Not Affect Their Diffusion and Distribution in Articular Cartilage
Tuomo S Silvast1, Jukka S Jurvelin2, Virpi Tiitu3
1SIB-Labs, University of Eastern Finland, Kuopio, Finland ; Department of Applied Physics, University of Eastern Finland, Kuopio, Finland ; Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland.
Contrast agent concentration does not affect its distribution in cartilage, but different agents like iodide and ioxaglate show varying diffusion and partition coefficients due to steric interactions. This finding is crucial for reliable contrast enhanced cartilage tomography (CECT) imaging.
Area of Science:
- Biomedical Engineering
- Radiology
- Materials Science
Background:
- Articular cartilage composition and structure influence contrast agent diffusion.
- Clinical contrast agent concentration in joint capsules can vary, potentially impacting contrast-enhanced cartilage tomography (CECT) reliability.
Purpose of the Study:
- To investigate the effects of varying x-ray contrast agent concentrations on diffusion and equilibrium distribution within cartilage.
- To assess the impact of concentration on contrast agent behavior for improved CECT interpretation.
Main Methods:
- Full-thickness bovine cartilage discs were used (n=120).
- Diffusion of ioxaglate and iodide at various concentrations was studied over 29 hours.
- Peripheral quantitative computed tomography (pQCT) was employed for imaging.
Main Results:
- Diffusion and partition coefficients were consistent across different concentrations of the same agent.
- Iodide exhibited a significantly greater diffusion coefficient (473 ± 133 µm²/s) compared to ioxaglate (92 ± 46 µm²/s).
- Iodide also showed a higher partition coefficient (71 ± 5%) than ioxaglate (62 ± 6%) in full-thickness cartilage after 29 hours.
Conclusions:
- Steric interactions significantly affect diffusion and partition coefficients between different contrast agents, even with similar charges.
- Increased solute concentration did not alter the partition coefficient, suggesting concentration independence for distribution.
- Maintaining consistent contrast agent concentration is vital for accurate interpretation of CECT imaging results.
