Comparison of biochemical cartilage imaging techniques at 3T MRI

摘要

Objective: To prospectively compare chemical-exchange saturation-transfer (CEST) with delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) and T2 mapping to assess the biochemical cartilage properties of the knee. Method: Sixty-nine subjects were prospectively included (median age, 42 years; male/female=32/37) in three cohorts: 10 healthy volunteers, 40 patients with clinically suspected cartilage lesions, and 19 patients about 1 year after microfracture therapy.T2 mapping, dGEMRIC, and CEST were performed at a 3T MRI unit using a 15-channel knee coil. Parameter maps were evaluated using region-of-interest analysis of healthy cartilage, areas of chondromalacia and repair tissue. Differentiation of damaged from healthy cartilage was assessed using receiver-operating characteristic (ROC) analysis. Results: Chondromalacia grade 2-3 had significantly higher CEST values (. P=0.001), lower dGEMRIC (T1-) values (. P<0.001) and higher T2 values (. P<0.001) when compared to the normal appearing cartilage. dGEMRIC and T2 mapping correlated moderately negative (Spearman coefficient r=-0.56, P=0.0018) and T2 mapping and CEST moderately positive (. r=0.5, P=0.007), while dGEMRIC and CEST did not significantly correlate (. r=-0.311, P=0.07). The repair tissue revealed lower dGEMRIC values (. P<0.001) and higher CEST values (. P<0.001) with a significant negative correlation (. r=-0.589, P=0.01), whereas T2 values were not different (. P=0.54). In healthy volunteers' cartilage, CEST and dGEMRIC showed moderate positive correlation (. r=0.56), however not reaching significance (. P=0.09). ROC-analysis demonstrated non-significant differences of T2 mapping vs CEST (. P=0.14), CEST vs dGEMRIC (. P=0.89), and T2 mapping vs dGEMRIC (. P=0.12). Conclusion: CEST is able to detect normal and damaged cartilage and is non-inferior in distinguishing both when compared to dGEMRIC and T2 mapping.