Clinical And Animal Experimental Study Of Reparative Cartilage After Matrix Associated Autologous Chondrocyte Implantation With MRI

Objective:To estimate zonal variation of GAG content in reparative cartilage after matrix associated autologous chondrocyte implantation (MACI) using delayed gadolinium-enhanced magnetic resonance imaging of the cartilage (dGEMRIC).Methods:Seven patients (14 cartilage defects) undergoing MACI were recruited for examination with dGEMRIC at 3,6, and 12 months after the procedure to calculate global and zonal longitudinal relaxivity (?R1) of the normal cartilage and reparative cartilage.Results:The mean ?R1 values of normal cartilage were significantly lower than those of reparative cartilage after MACI. A significant increase was noted in the mean ?R1 values from the deep layer to the superficial layer in the reparative cartilage at the 3 examinations. The ?R1 values of the reparative cartilage showed no significant variation between 3 months and 6 months, but a significant decrease in the ?R1 values occurred at 12 months.Conclusion:dGEMRIC is feasible to assess cartilage repair noninvasively following MACI.Objective:To investigate the value of T2mapping and delayed gadolinium-enhanced magnetic resonance imaging of the cartilage (dGEMRIC) in estimating cartilage repair process after matrix associated autologous chondrocyte implantation (MACI) in a sheep model.Methods:Eight sheep with sixteen knees which underwent MACI accepted MRI examination?gross observation and histological evaluation 6 and 12 months later (All right knees of eight sheep received MACI 6 months later than all left knees). To apply T2mapping and dGEMRIC to calculate T2 values and longitudinal relaxivity(?R1) of normal cartilage and reparative cartilage. The comparison of T2 and ?R1 values between normal cartilage and reparative cartilage at the same time was analyzed with pair t test. Independent-samples t test was used to compare the difference of T2 and ?R1 values of reparative cartilage between 6 and 12 months after MACI.Results:The mean T2 and ?R1 values of normal cartilage were significantly lower than reparative cartilage after MACI. The comparison of T2 and ?R1 values of reparative cartilage showed a significant decrease from 6 months to 12 months. The gross and histological observation showed that reparative cartilage 12 months later is more comparable to normal cartilage than 6 months later.Conclusion:T2mapping and dGEMRIC can provide biochemical information of reparative cartilage and noninvasively assess the repair effect after MACI.