Delayed Computed Tomography Arthrography of Human Knee Cartilage In Vivo

OBJECTIVE We investigated the feasibility of delayed computed tomography (CT) arthrography for evaluation of human knee cartilage in vivo. Especially, the diffusion of contrast agent out of the joint space and the optimal time points for imaging were determined. DESIGN Two patients were imaged using delayed CT arthrography and delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) techniques. RESULTS Two hours after injection, the concentration of contrast agent in the joint space was still high enough (20% to 24.5% of the initial concentration at 0 minutes) to allow delayed CT arthrography. The half-life of the contrast agent in the joint space varied from 30 to 60 minutes. The contrast agent concentration in patellar and femoral cartilage reached the maximum after 30 and 60 minutes, respectively. According to dGEMRIC, there were no differences between patients. However, in delayed CT arthrography, the penetration of the contrast agent was higher in the osteoarthritic knee cartilage. CONCLUSIONS Contrast agent remained in the joint space long enough to enable delayed CT arthrography of cartilage. After 30 minutes, the normalized contrast agent concentration was higher in the cartilage of the osteoarthritic knee in comparison with the healthy knee. To conclude, delayed CT arthrography exhibited potential for use in the clinical evaluation of cartilage integrity.