Quantitative evaluation of muscle atrophy and fatty infiltration in chronic supraspinatus tendon tear

WANG Xiang; QU Jin; LEI Xinwei

doi:10.19300/j.2017.L5163zt

Abstract：Objective The purpose of this study was to quantify the fat content of muscles with mDIXON-Quant technique, and to investigate the relationship between fatty infiltration, muscle atrophy, and tendon tear severity (TTS) of supraspinatus. Methods 85 subjects who showed clinical shoulder symptoms and underwent shoulder MR imaging (in-cludes mDIXON-Quant) were enrolled. Fat fraction (FF) maps were obtained by using mDIXON-Quant. Relative supraspinatus size (RSS)was used as index of muscle atrophy. The supraspinatus was graded into 4 groups based on routine MRI-findings to characterize the TTS:normal, degeneration, partial-thickness tear, and complete tear. Comparisons of RSS between groups were tested by One-way ANOVA analysis with Post Hoc Scheffe paired comparison test. Comparisons of FF between groups were tested by Welch's approximate F test with Post Hoc Dunnett's T3 method. Correlation of FF, RSS, and TTS were analyzed with Spearman correlation analysis. Results There were significant differences in the FF and RSS among all the groups (P<0.05). The RSS was significantly lower in the complete tear group than the normal and degeneration groups (P<0.05);the FF was significantly higher in complete tear group than the partial-thickness tear, de-generation, and normal groups; the FF was higher in the partial-thickness tear group than the degeneration and normal groups, FF was higher in the degeneration group than the normal group (P<0.05). There was a negative correlation between RSS and TTS (rs=-0.384, P<0.001). There was a positive correlation between FF and TTS (rs=0.808, P<0.001).There was a negative correlation between RSS and FF (rs=-0.495, P<0.001). Conclusion mDIXON-Quant can quantitatively evaluate the level of fat infiltration after various degrees of TTS.