Selective visualization of rabbit knee cartilage using MR imaging with a double-contrast agent

Abstract

To establish a reliable method and efficient contrast agent for selective MR imaging of articular cartilage to improve the diagnosis of cartilage disorders. A standard trace element replenisher (Mineric), which includes manganese chloride, cupric sulfate (both positive MR contrast agents), and colloidal ferric chloride (a negative contrast agent), was evaluated in comparison with gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) as a potential contrast agent. Normal saline was used as a control. The agents were injected into bilateral knee joints, and the entire joint block was dissected. Coronal images of femorotibial joints were obtained at 7.05 Tesla. Signal intensity ratios (SIRs) of cartilage to joint fluid were calculated for T1 and T2 values. The side effects of the agents were also investigated. Finally, histological evaluations were performed. SIRs were significantly increased in the Mineric treatment group compared with the Gd-DTPA and saline treatment groups. The T1 values of cartilage and fluid were significantly decreased in the Gd-DTPA and Mineric treatment groups. The T2 values of fluid were significantly decreased in the Mineric treatment group. No apparent side effects or degenerative changes in the joints were observed. A clinical trace element mixture was used as a novel double-contrast agent, and it exhibits selective MR contrast in articular cartilage.