Abstract: 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 decrease 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.