Cationic contrast agents improve quantification of glycosaminoglycan (GAG) content by contrast enhanced CT imaging of cartilage

• Published in: Journal of orthopaedic research 2011-05, Vol.29 (5), p.704-709
• Main Authors: Bansal, Prashant N., Joshi, Neel S., Entezari, Vahid, Malone, Bethany C., Stewart, Rachel C., Snyder, Brian D., Grinstaff, Mark W.
• Format: Article
• Language: English
• Subjects: Animals; Benzamides; Cartilage, Articular - chemistry; Cartilage, Articular - diagnostic imaging; cationic; Cations; Cattle; computed tomography (CT); contrast agent; Contrast Media; Extracellular Matrix - chemistry; glycosaminoglycans (GAGs); Glycosaminoglycans - analysis; proteoglycans; Rabbits; Tomography, X-Ray Computed - methods; Triiodobenzoic Acids
• ISSN: 0736-0266; 1554-527X
• DOI: 10.1002/jor.21312

Minimally invasive and non‐destructive methods to quantify glycosaminoglycans (GAGs) in articular cartilage extracellular matrix are of significant interest for the biochemical analysis of cartilage and diagnosis and tracking of osteoarthritis in vivo. Here, we report the use of cationic iodinated contrast agents in comparison to conventional anionic contrast agents for the quantitative monitoring of GAG concentrations with peripheral quantitative computed tomography. Using an ex vivo bovine osteochondral plug model, the cationic contrast agents were evaluated for their ability to distribute into articular cartilage and generate a positive relationship with GAG content. The cationic agents resulted in much higher equilibrium X‐ray attenuations in cartilage extracellular matrix (ECM) than anionic agents. Experiments with samples subjected to enzymatic GAG degradation demonstrated that the cationic agents were up to five times more sensitive (p = 0.0001) to changes in GAG content and had a 24% higher correlation (p = 0.002) compared to the anionic agent (R2 = 0.86, p