In vivo MRI of fresh stored osteochondral allograft transplantation with delayed gadolinium‐enhanced MRI of cartilage: Protocol considerations and recommendations

The protocol for delayed gadolinium‐enhanced MRI of cartilage (dGEMRIC) was adapted for the evaluation of transplanted osteochondral allograft cartilage. Eight patients with focal grade 4 cartilage defects of the femoral condyle were treated with single cylindrical osteochondral allografts. At 1 and 2 years, dGEMRIC image sequences were acquired and regions of interest (ROIs) were drawn in repair and native control cartilage. Mean T 1 values of region of interest were used to calculate established dGEMRIC metrics. The correlation was measured between the Δ R 1 and R 1 ‐Post metrics for repair and native cartilage. T 1 times were measured in deep and superficial zones of cartilage. A strong correlation was identified between full‐thickness, deep, and superficial Δ R 1 and R 1 ‐Post values for native cartilage and repair cartilage for all years (range: 0.893–1.0). The mean T 1 times and Δ R 1 rate between deep and superficial regions of articular cartilage were statistically different for all regions of the distal femora analyzed at 1 year and 2 years after osteochondral allograft transplantation ( P < 0.05). The dGEMRIC pre‐Gadolinium scan is unnecessary when evaluating transplanted osteochondral allograft cartilage. The observation of stratified T 1 and Δ R 1 values indicates a need to re‐evaluate the methodology behind the placement of region of interest in dGEMRIC. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.