T2 mapping of cartilage and menisci at 3T in healthy subjects with knee malalignment: initial experience

Purpose To assess the relationship between knee alignment and T2 values of femorotibial cartilage and menisci in healthy subjects at 3T. Materials and methods Thirty-six healthy subjects divided into three subgroups of 12 neutral, 12 varus, and 12 valgus alignment of the femorotibial joint were investigated on 3-T MR scanner using a 2D multi-echo turbo spin-echo (TSE) sequence for T2 mapping. Wilcoxon signed-rank test and analysis of covariance (ANCOVA) were performed to determine any statistically significant differences in subregional T2 values of femorotibial cartilage and menisci among the three subgroups of healthy subjects. Results Lateral femoral anterior cartilage subregion (523 ms, mean +/- standard deviation; 53 +/- 2 ms) had significantly higher T2 values (p<0.05) than medial femoral anterior cartilage subregion (51 +/- 2 ms; 51 +/- 2 ms) in varus and valgus groups, respectively. There were statistically significant differences (p<0.05) in T2 values of tibial central cartilage subregion between lateral and medical compartment among varus, valgus, and neutral subgroups. Lateral body segment of meniscus (41 +/- 3 ms) had significantly higher (p<0.05) T2 values than medial body segment (40 +/- 2 ms) in the varus subgroup. Conclusions Some degree of correlation between knee alignment and subregional T2 values of femorotibial cartilage and menisci exists in healthy subjects. These findings indicate that T2 mapping may be sensitive in assessing the load distribution pattern of human cartilage and menisci with knee alignment abnormality, which may be used as reference baseline when understanding the occurrence and progression of knee osteoarthritis.