Contrast enhanced CT attenuation correlates with the GAG content of bovine meniscus

We determined whether contrast‐enhanced computed tomography (CECT) attenuation obtained using a µCT scanner correlated with the glycosaminoglycan (GAG) content and distribution in ex vivo bovine menisci. Bovine samples were immersed in different concentrations of the contrast agents CA4+ and Ioxaglate, and the µCT images were compared to Safranin‐O staining. CA4+ and Ioxaglate diffusion‐in kinetics and the correlation between their CECT attenuations and GAG content were investigated. CA4+ and Ioxaglate both reached steady state in the meniscal regions within 95 h, with tau values of 20.6 ± 3.98 and 25.9 ± 3.71 h (mean ± SD), respectively. Both agents diffused preferentially through the proximal and secondarily through the distal surface. The CA4+ CECT attenuation was strongly and positively correlated with the GAG content of the meniscus regions ( R 2  = 0.89, p  < 0.001) at low concentrations (12 mgI/ml), while the Ioxaglate CECT attenuation was moderately and negatively correlated with the GAG content ( R 2  = 0.51, p  = 0.03) at 60 mgI/ml. CECT can image ex vivo menisci, and the CA4+, compared to Ioxaglate, enhanced attenuation strongly correlates with the GAG content and distribution in bovine meniscus. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:1765–1771, 2013